BIOIGSY 


BIOLOGY 
LIBRARY 


FRONTISPIECE,  i,  cell  of  fleshy  scale  of  bulb  of  onion  (Allium  Cepa)  showing  cyto- 
plasm, nucleus  and  large  central  vacuole. 

Chloroplasts:  2,  a  parenchyma  cell  of  green  fruit  of  garden  pepper  (Capsicum  annuum) 
showing  cytoplasm,  nucleus  and  chloroplasts;  2a,  a  chloroplast  of  a  moss  (Funaria)  showing 
green  granules,  assimilation  starch  grains  and  protein  granules;  2b,  a  cell  near  the  periphery 
of  the  pseudo-bulb  of  the  orchid  (Phaius  grandifolius)  showing  cytoplasm  and  three  reserve 
starch  grains  formed  by  leucoplasts,  which  latter  under  the  influence  of  light  have  developed 
into  chloroplasts. 

Chromoplasts:  3,  a  parenchyma  cell  of  ripe  fruit  of  Capsicum  annuum  showing  cyto- 
plasm, nucleus  and  yellowish-red  chromoplasts;  3a,  isolated  chromoplasts  of  carrot  (Daucus 
Car  ota). 

4,  transverse  section  of  petal  of  wild  pansy  (Viola  tricolor)  showing  colored  cell-sap  in 
epidermal  cells. 


APPLIED  AND  ECONOMIC 

BOTANY 


ESPECIALLY  ADAPTED  FOR  THE  USE  OF  STUDENTS  IN 
TECHNICAL  SCHOOLS,  AGRICULTURAL,  PHARMACEU- 
TICAL AND  MEDICAL  COLLEGES,  AND  ALSO  AS  A  BOOK 
OF  REFERENCE  FOR  CHEMISTS,  FOOD  ANALYSTS 
AND  STUDENTS  ENGAGED  IN  THE  MORPHOLOGI- 
CAL AND  PHYSIOLOGICAL  STUDY  OF  PLANTS 


BY 

HENRY  KRAEMER,   Ph.B.  (in  Chemistry),  Ph.M. 
(in  Pharmacy),  Ph.D.  (in  Botany). 

PROFESSOR  OF  BOTANY  AND  PHARMACOGNOSY,  AND  DIRECTOR  OF  THE  MICROSCOPICAL  LABORA- 
TORY IN  THE  PHILADELPHIA  COLLEGE  OF  PHARMACY;  MEMBER  OF  THE  EXECUTIVE  COM- 
MITTEE OF  REVISION  OF  THE  PHARMACOPOEIA  OF  THE  UNITED  STATES  OF  AMERICA; 
CORRESPONDING  MEMBER  OF  THE  SOCIETE  DE  PHARMACIE  DE  PARIS,  ETC. 


ILLUSTRATED 

With  424  plates,  comprising  about  2000  figures 


PUBLISHED  BY  THE  AUTHOR 

145  NORTH  TENTH  ST., 

PHILADELPHIA 


COPYRIGHT,  1914,  BY  HENRY  KRAEMER 


ALL  RIGHTS  RESERVED 

\ 

•W 


•;  •  r«          •  •"  c  •  •;  ; 

.  v  ::/ 


\\  / 

BIOLOGY 

MBRARY 

G 


PREFACE. 

THERE  are  quite  a  number  of  books  on  botany,  many  of  which  serve 
a  very  excellent  purpose.  For  the  most  part,  however,  they  are  not  adapted 
for  the  use  of  students  in  the  applied  sciences  where  the  knowledge  of 
botany  is  to  be  utilized  later  in  practical  work.  It  is  now  more  than  sixty 
years  since  Schleiden  showed  the  value  of  the  microscope  in  the  examina- 
tion of  drugs  and  Schacht  demonstrated  its  usefulness  in  the  study  of 
textile  fibers.  Since  that  time  quite  a  number  of  works  have  been  pub- 
lished dealing  with  the  microscopy  of  special  technical  products,  as  drugs, 
foods,  fibers,  woods,  etc.,  but  there  have  been  no  text-books  which  could 
be  employed  in  the  courses  on  applied  and  economic  botany  that  would 
satisfy  either  the  desires  of  the  student  or  fit  the  graduate  for  practical  work 
in  commercial  life.  It  is  not  generally  appreciated  that  there  is  a  depart- 
ment of  applied  botany  which  is  distinct  from  every  other  phase  of  botani- 
cal study ;  the  point  of  view  and  the  technique  being  peculiarly  its  own  and 
the  problems  so  intricate  and  important  that  they  should  ever  be  held  be- 
fore the  student  and  command  his  constant  attention.  It  is  almost  self- 
evident  that  courses  in  botany  which  are  intended  for  intellectual  culture 
or  scientific  discipline  are  not  adapted  for  technical  courses  of  instruction. 
In  the  latter  the  student  has  a  right  to  ask  for  the  application  of  the  in- 
struction which  he  is  receiving  and  to  show  an  interest  in  proportion  as  the 
instructor  is  able  to  demonstrate  its  value.  There  are  some  who  consider 
that  a  more  or  less  superficial  knowledge  of  botanical  principles  and  micro- 
scopic technique  is  sufficient  for  the  student  in  applied  or  economic  botany. 
On  the  contrary,  we  find  that  a  rather  extended  knowledge  of  botany  and 
a  very  thorough  preparation  in  certain  phases  of  botanical  work  are 
absolutely  required  in  order  to  prepare  him  to  meet  and  solve  the  many 
problems  that  arise  in  the  commercial  world.  Many  of  the  commercial 
problems  that  are  held  to  be  chemical  and  which  are  handed  to  the  chem- 
ist for  solution  are,  as  a  matter  of  fact,  of  a  botanical  character  and  can 
be  solved  with  less  expense  and  less  time  by  the  trained  botanist.  What 
is  really  needed  is  the  trained  analyst,  who,  while  proficient  with  chemical 
methods,  is  also  thoroughly  versed  in  microscopic  technique.  We  have 
come  to  a  time,  if  real  progress  is  to  be  made  both  in  the  manufacture  of 
plant  materials  and  in  the  examination  of  commercial  substances,  that  it 
is  necessary  to  bring  both  chemical  and  botanical  training  and  knowledge 
to  bear  upon  the  problems  involved. 

Nearly  all  of  the  problems  upon  which  one  is  liable  to  be  consulted  in 
active  practice,  whether  they  involve  new  processes  of  manufacture  or 
the  examination  of  the  finished  market  material,  show  at  the  outset  that 
the  analyst  must  have  a  very  thorough  knowledge  of  the  cell  constituents 
and  the  tissues  composing  the  raw  material.  It  is  for  this  reason  that 
almost  one-half  of  the  material  of  this  volume  is  devoted  to  the  study  of 


iv  PREFACE. 

cell-contents,  forms  of  cells,  and  the  outer  and  inner  morphology  of  higher 
plants.  The  facts  and  illustrations  here  presented  cover  not  only  the  latest 
researches  on  their  morphology,  origin,  and  distribution,  but  also  the 
most  recent  advances  in  regard  to  their  chemical  nature.  A  fair  amount 
of  this  work  is  original,  and  the  presentation  in  one  volume,  it  is  hoped, 
will  be  appreciated  in  addition  also  by  students  of  the  plant  cell  as  well 
as  the  phyto-chemist. 

In  the  practical  examination  of  the  crude  materials  of  the  market  we 
find  more  or  less  contamination  with  fungi,  lichens,  and  other  lower  plants, 
and  for  this  reason,  as  well  as  for  the  understanding  of  the  morphology  of 
the  higher  plants,  a  more  or  less  succinct  treatment  of  the  Principal  Groups 
of  Plants  is  given  in  Chapter  I.  Another  reason  which  has  prompted  the 
author  to  lay  considerable  stress  on  the  knowledge  contained  in  this  chap- 
ter is  that  if  the  student  will  master  the  technique  and  will  apply  himself 
to  this  part  of  the  work,  he  will  be  better  prepared  to  take  up  the  study 
of  the  structures  of  higher  plants. 

The  chapter  on  Classification  of  Higher  Plants  is  quite  extended  and 
illustrated  with  a  large  number  of  photographs,  showing  not  only  many 
of  our  interesting  wild  plants  but  the  principal  economic  plants  that  are 
used  as  foods,  drugs,  and  for  other  economic  purposes,  with  considerable 
valuable  technical  information  concerning  them.  The  chapter  on  Nomen- 
clature has  been  included  in  order  that  the  derivations  of  botanical  names 
might  be  better  understood  and  their  correct  spelling  facilitated.  The 
chapter  on  Cultivation  of  Medicinal  Plants,  while  especially  prepared  for 
those  interested  in  the  subject,  will  be  found  useful  to  those  interested  in 
other  industries  where  the  extermination  of  native  plants  is  calling  attention 
to  practical  means  for  their  replenishment.  The  chapter  on  Microscopic 
Technique  contains  methods  for  the  preparation  of  commercial  materials 
and  much  information  that  doubtless  will  facilitate  practical  work.  The 
index  contains  some  6,000  titles,  making  the  information  contained  in  this 
volume  readily  accessible. 

The  work  is  illustrated  throughout,  and  the  legends  accompanying  the 
illustrations  will  be  found  interesting  and  instructive  and  in  most  instances 
supplement  the  information  given  in  the  text.  All  of  the  illustrations  which 
are  not  reproductions  of  photographs  and  drawings  made  by  the  author 
are  duly  credited.  The  author  acknowledges  the  valuable  services  rendered 
by  his  associates  in  the  preparation  of  the  text,  reading  of  proof,  and  prep- 
aration of  the  index;  to  Professor  Wallace  Truesdell  for  assistance  in 
the  chapter  on  Botanical  Nomenclature  and  to  Mr.  Stewardson  Brown  for 
the  use  of  a  number  of  photographs.  When  larger  monographs  and 
authoritative  works  have  been  consulted,  due  credit  has  been  given  in  the 
text,  so  that  the  present  work  is  a  foundation  not  only  of  a  text-book  for 
students  of  applied  and  economic  botany  but  as  a  reference  book  for  manu- 
facturers and  analysts. 

NOVEMBER,  1014.  H.  K. 


CONTENTS. 


CHAPTER  I.— PRINCIPAL  GROUPS  OF  PLANTS. 

PAGE 

INTRODUCTORY i 

THALLOPHYTES 5 

Schizophy  tes 7 

Schizophyceae  (Fission  Algae) 3 

Schizomycetes  (Bacteria) I2 

Algae I6 

Chlorophyceae  (Green  Algae) 20 

Phaeophyceae  (Brown  Algae) 28 

Rhodophyceae  (Red  Algae) 31 

Diatoms 35 

Fungi 40 

Phycomycetes  (Alga-like  Fungi) 42 

Ascomycetes  (Including  Yeasts) 47 

Basidiomycetes 56 

Fungi  Imperfecti 70 

Lichens 71 

ARCHEGONIATES 75 

Bryophytes 76 

Hepaticae  (Liverworts) 80 

Musci  (Mosses) 84 

Pteridophytes ; .  86 

Filicales  (Ferns) 87 

Equisetales  (Horsetails) . ." 96 

Lycopodiales  (Club  Mosses) 97 

SPERMOPHYTES  (SEED  PLANTS) 100 

Gymnosperms 101 

Angiosperms 119 

ORGANIC  EVOLUTION 128 

CHAPTER  IL— CELL-CONTENTS  AND  FORMS  OF  CELLS.. 

PROTOPLASMIC  CELL-CONTENTS 134 

NON-PROTOPLASMIC  CELL-CONTENTS 140 

FACTORS  INFLUENCING  GROWTH,  INCLUDING  FOOD  OF  PLANTS 246 

FORMS  OF  CELLS 262 

Parenchyma 262 

Mechanical  Tissue 264 

Conducting  or  Mestome  Cells 272 

Protecting  Cells 277 

v 


vi  CONTENTS. 

CHAPTER    III.— OUTER    AND    INNER    MORPHOLOGY    OF    THE 

HIGHER  PLANTS. 

INTRODUCTORY 298 

I.  Outer  Morphology  .of  the  Root 299 

Inner  Structure  of  the  Root 309 

II.  Outer  Morphology  of  the  Stem 320 

Inner  Structure  of  the  Stem 338 

III.  Outer  Morphology  of  the  Leaf 348 

Inner  Structure  of  the  Leaf 365 

IV.  Outer  Morphology  of  the  Flower 374 

Inner  Structure  (Histology)  of  the  Flower 402 

V.  Outer  Morphology  of  the  Fruit 408 

Inner  Structure  of  the  Fruit 42-1 

VI.  Outer  Morphology  of  the  Seed ...  v. 423 

Inner  Structure  of  the  Seed , 427 

CHAPTER  IV.— BOTANICAL  NOMENCLATURE 430 

CHAPTER    V.— CLASSIFICATION    OF    ANGIOSPERMS    YIELDING 
ECONOMIC  PRODUCTS. 

INTRODUCTORY 463 

MONOCOTYLEDONS 463 

DICOTYLEDONS 501 

Archichlamydeas  or  Choripetalae 504 

Metachlamydese  or  Sympetalae , 643 

CHAPTER  VI.— CULTIVATION  OF  MEDICINAL  PLANTS 

PLANTS  GROWN  FROM  SEEDS .• 728 

PROPAGATION  BY  CUTTING 733 

COLLECTING  AND  DRYING  OF  DRUGS 737 

RELATIVE  VALUE  OF  DRUGS  FROM  CULTIVATED  AND  WILD  PLANTS  ....  739 
PROGRESS  IN  THE  UNITED  STATES 744 

CHAPTER    VII.— MICROSCOPIC    TECHNIQUE    AND    REAGENTS. 

MAKING  OF  SECTIONS 749 

PRACTICAL  SUGGESTIONS 751 

MlCROMETRY  OR  MICROSCOPIC  MEASUREMENT 754 

REAGENTS 755 

EFFECTS  OF  IMPORTANT  MICRO-CHEMICAL  REAGENTS 759 

THE  MICRO-POLARISCOPE 764 

THE  SPECTROSCOPE  IN  MICROSCOPIC  ANALYTICAL  WORK 764 

DARK  FIELD  ILLUMINATION  AND  THE  ULTRA-MICROSCOPE 765 

MICRO-ANALYSIS 766 


BOTANY 

CHAPTER  I 
PRINCIPAL  GROUPS  OF  PLANTS 

INTRODUCTORY 

THERE  are  four  main  lines  of  botanical  work  now  recognized, 
— namely,  Morphology,  Histology,  Physiology,  and  Ecology. 
MORPHOLOGY  treats  of  the  form  and  structure  of  plants  and  the 
subject  is  sometimes  divided  into  (i)  external  morphology  or 
organography  and  (2)  internal  morphology  or  anatomy  (histol- 
ogy). The  former  deals  with  external  characters  of  plant  parts  and 
the  latter  with  their  minute  inner  structure.  PHYSIOLOGY  may  be 
defined  as  the  study  which  considers  life  processes  and  the  condi- 
tions which  influence  these.  ECOLOGY  is  the  study  of  the  adapta- 
tion of  plants  and  their  parts  to  external  conditions.  It  is  impor- 
tant to  bear  in  mind,  however,  that  these  several  departments 
are  more  or  less  interdependent,  and  that  one  of  them  cannot  be 
intelligently  studied  without  a  consideration  of  the  problems  of 
the  others.  For  instance,  as  Goebel  states,  we  cannot  under- 
stand the  relation  of  the  external  forms  of  organs  without  refer- 
ence to  their  functions.  In  other  words,  form  and  function  have 
a  direct  relation ;  one  influences  the  other.  So,  too,  in  the  study 
of  ecology  we  study  the  influence  of  external  conditions  on 
plants  and  these,  as  indicated  above,  have  a  direct  influence  on 
physiological  processes,  and  thus  the  study  of  ecology  merges 
into  the  study  of  physiology  on  the  one  hand  and  into  morphology 
on  the  other. 

While  this  book  will  deal  chiefly  with  the  structure  of  plants 
and  their  parts,  still  it  will  be  necessary  occasionally  to  refer  to 
some  of  the  characters  of  plants  which  properly  belong  to  other 
departments  of  botanical  study. 

>     Basis  of  Plant  Structure. — In  order  to  understand  the  sig- 
nificance and  relation  of  the  various  parts  of  plants  it  is  necessary 

i 


2  A  TEXT-BOOK  OF  BOTANY. 

to  know  something  of  their  functions  and  habits  of  life  as  well 
as  of  their  internal  structure.  It  is  desirable  at  this  point  to  give  a 
brief  consideration  to  the  cell,  as  it  is  the  unit  of  plant  structure. 

If  we  make  a  section  of  a  plant  and  examine  it  by  means  of 
the  microscope,  the  cut  surface  presents  the  appearance  of  a 
network,  indicating  that  the  tissue  is  made  up  of  small  compart- 
ments or  chambers.  One  of  these  compartments  together  with 
its  contents  constitutes  the  structure  known  as  the  CELL  (see 
Frontispiece). 

The  cell-contents  vary  greatly  in  appearance  and  composi- 
tion, but  in  all  active  or  living  cells  there  is  always  present  the 
substance  known  as  PROTOPLASM.  The  protoplasm  is  the  basis 
of  all  plant  structures  whether  they  belong  to  the  lowest  or  high- 
est forms ;  for  by  its  aid  or  from  it  all  parts  of  the  plant  are 
developed.  Even  the  cell-wall  is  a  product  of  protoplasmic  activity. 
The  protoplasmic  content  of  the  cell  consists  of  several  intimately 
related  but  more  or  less  distinct  portions, — namely,  a  somewhat 
thin,  semi-liquid,  granular  portion  known  as  the  CYTOPLASM  ; 
a  more  or  less  spherical  body  embedded  in  the  cytoplasm  called 
the  NUCLEUS  ;  and  frequently,  but  not  always,  certain  small 
bodies  which  are  more  or  less  variable  in  shape  called  PLASTIDS, 
these  being  also  embedded  in  the  cytoplasm  (see  Frontispiece). 
The  cytoplasm  and  nucleus  are  sometimes  considered  together 
as  a  unit,  which  is  known  as  the  PROTOPLAST.  A  fuller  discussion 
of  the  differentiated  portions  of  the  protoplasm  will  be  found  in 
Chapter  II. 

The  lowest  organisms,  as  the  slime  molds,  do  not  have  an 
enclosing  membrane,  but  consist  of  a  naked  mass  of  protoplasm. 
With  this  exception  plants  have  an  outer  wall  or  membrane. 
They  may  consist  of  a  single  cell,  as  in  the  Bacteria,  or  a  chain 
of  cells,  as  in  the  filamentous  Algae,  or  a  mass  of  cells,  as  in  the 
majority  of  plants,  and  are  accordingly  designated  as  unicellular 
or  multicellular.  The  cell-wall  is  composed  for  the  most  part 
of  cellulose,  but  may  be  modified  in  various  ways. 

Nomenclature. — The  names  for  describing  plants  have  been 
derived  for  the  most  part  from  studies  of  the  higher  plants,  they 
having  exclusively  attracted  the  attention  of  botanists  at  first. 
But  with  the  light  which  has  been  thrown  on  the  relationship 


PRINCIPAL  GROUPS  OF  PLANTS.  3 

of  the  higher  and  lower  groups  of  plants  by  the  more  recent 
study  of  the  lower  forms  the  older  terminology  has  been  somewhat 
modified.  Thus,  for  example,  we  speak  of  the  root  and  shoot, 
with  its  leaves,  as  the  vegetative  organs  of  the  higher  plants, 
and  in  describing  the  corresponding  organs  (where  they  exist)  in 
the  lower  plants,  we  either  apply  these  terms  directly,  or  indi- 
rectly by  saying  that  the  latter  are  root-like,  stem-like,  etc.  On 
the  other  hand,  we  now  speak  of  the  sexual  organs  of  the  higher 
plants  as  antheridia  and  oogonia  (or  archegonia)  instead  of 
classifying  them  roughly  as  stamens  and  pistils,  the  latter  names 
being  retained  but  with  a  different  signification. 

Plant  Organs. — Depending  upon  the  fact  that  the  plant  re- 
quires nourishment  for  its  growth  and  development  and  that  it 
has  also  to  carry  on  the  work  of  reproduction  or  propagation, 
— i.e.,  the  production  of  new  plants, — we  distinguish  between 
vegetative  or  nutritive  organs  and  propagative  or  reproductive 
organs.  The  vegetative  organs,  such  as  the  root,  stem  and  leaves 
in  higher  plants,  manufacture  the  food  necessary  for  the  life  of 
the  plant,  while  certain  other  more  or  less  specialized  organs  or 
cells  carry  on  the  work  of  reproduction. 

In  the  lower  plants,  however,  the  whole  structure  is  much 
simpler,  and  in  some  instances  a  cell  which  performs  the  work 
of  a  nutritive  cell  at  one  stage  may  become  a  reproductive  cell 
at  another,  or,  as  in  the  case  of  the  unicellular  Algae,  all  the 
various  functions  of  the  plant  may  be  carried  on  by  a  single  cell. 

Generally  speaking,  there  are  two  principal  ways  in  which 
plants  are  multiplied  or  reproduced  :  ( i )  By  CELL  DIVISION  or  cell 
fission,  and  (2)  by  the  formation  of  special  cells  known  as 
SPORES.  In  cell  division  (Fig.  85)  the  nucleus  and  cytoplasm  of 
a  cell  divide  to  form  two  new  cells  or  protoplasts,  which  become 
distinct  by  the  formation  of  a  wall  or  cell-plate  between  the  two 
halves.  All  growth  in  plants  is  dependent  upon  this  method, 
and  in  growing  parts  the  cells  are  said  to  be  in  a  state  of  division. 
Owing  to  the  plasticity  of  the  plant  organism,  detached  portions 
will  often  grow  and  give  rise  to  new  plants,  as  in  the  case  of  cut- 
tings. Growth  here  as  in  the  parent  plant  is  accompanied  by  cell 
division.  In  some  of  the  lower  Algae  (Fig.  10)  cell  division  is  the 
only  method  of  propagation,  and  as  only  the  ordinary  vegetative  or 


4  A  TEXT-BOOK  OF  BOTANY. 

nutritive  cells  of  the  plant  are  involved  in  the  process  it  is  some- 
times spoken  of  as  vegetative  multiplication. 

In  both  lower  and  higher  plants,  with  the  exceptions   just 
noted,  reproduction  is  also  carried  on  by  means  of  spores. 


FIG.  5.  Ulothrix  zonata.  A,  young  filament  with  rhizoid  cell  (r);  B,  piece  of  filament 
showing  escape  of  swarm  spores;  C,  a  swarm  spore  or  zoospore  with  4  cilia;  D,  biciliate 
gametes  escaping  from  a  filament;  E,  F,  G,  showing  different  stages  of  union  of  two  gametes; 
H,  young  zygote  or  zygospore  in  which  the  cilia  have  been  absorbed;  J,  i-celled  plant 
developed  from  zygote;  K,  young  plant  organizing  zoospores. — After  Dodel-Port. 

Depending  upon  their  origin  two  classes  of  spores  are  distin- 
guished, namely,  (a)  asexual  spores,  and  (b)  sexual  spores.  In 
,the  production  of  asexual  spores  the  contents  of  a  certain  cell 
called  a  mother  cell  or  SPORANGIUM  break  up  into  a  number  of 
new  cells  sometimes  called  daughter  cells,  which  escape  through 
the  cell-wall.  In  the  lower  plants,  particularly  those  growing 


PRINCIPAL  GROUPS  OF  PLANTS.        5 

in  water  or  in  moist  places,  these  cells  are  provided  with  short 
thread-like  appendages  known  as  cilia,  which  enable  them  to 
move  about  in  the  water.  They  are  known  as  ZOOSPORES  or  swarm 
spores  (Fig.  5,  B,  C),  and  each  individual  zoospore  is  able  to 
produce  a  new  plant. 

The  number  of  zoospores  formed  in  a  sporangium  is  usually 
2  to  8,  as  in  Ulothrix,  but  the  number  may  be  larger.  The  method 
of  cell  formation  which  gives  rise  to  zoospores  is  sometimes 
spoken  of  as  INTERNAL  DIVISION  from  the  fact  that  they  arise 
within  the  old  cell  and  retain  no  relation  to  the  old  wall  as  is  the 
case  in  cell  fission.  The  zoospores  are  at  first  naked  protoplasts, 
but  later,  on  coming  to  rest,  may  form  a  wall.  Sexual  spores,  on 
the  other  hand,  are  formed  by  the  union  of  two  cells  known  as 
GAMETES.  When  the  gametes  are  similar  the  resulting  spore  is 
known  as  a  ZYGOSPORE  or  zygote  (Fig.  5,  E,  F,  G).  When  the 
gametes  are  unlike,  the  spore  produced  by  their  union  is  known 
as  an  OOSPORE.  In  the  latter  case  one  of  the  gametes  is  larger 
than  the  other,  is  less  active,  and  is  spoken  of  as  the  female 
gamete,  oosphere,  or  egg  (Figs.  12,  21).  The  other  more  active 
cell  is  known  as  the  male  gamete,  antherozoid  or  sperm  (Fig. 
51,  ///).  The  cell  giving  rise  to  the  oosphere  is  known  as  the 
oogonium  (Figs.  12,  21),  while  the  one  in  which  the  anthero- 
zoid or  sperm  originates  is  called  the  antheridium  (Figs.  12,  '21, 

22,  51). 

PLANT  GROUPS. 

Until  a  comparatively  recent  time,  botanists  divided  the  plant 
kingdom  into  two  large  groups,  as  follows : 

The  flowering  plants,  or  Phanerogams,  meaning  "  reproductive 
process  evident,"  so  applied  because  the  reproduction  of  the  plant 
was  readily  seen  to  develop  in  the  flower  through  the  agency  of 
the  pistil  and  stamens. 

The  non-flowering  plants,  or  Cryptogams,  meaning  "  repro- 
ductive process  concealed,"  so  applied  to  the  lower  plants  like 
the  ferns,  mosses,  sea-weeds,  etc.,  because  in  these  plants  the 
method  of  reproduction  was  not  known. 

Now,  however,  after  a  considerable  amount  of  study,  it  has 
been  learned  that  a  great  many  of  the  lower  plants  have  repro- 


6  A  TEXT-BOOK  OF  BOTANY. 

ductive  organs  which  are  analogous,  even  if  they  are  not  exactly 
similar,  to  those  of  the  flowering  plants.  Consequently  the  former 
classification  is  no  longer  applicable,  and  the  following  arrange- 
ment is  now  generally  adopted  : 


Thallophytes    ....... 

I  Fungi 

Archegoniates    ......  (  Bryophytes 

(  Pteridophytes. 

Spermophytes    ......  j  Gymnosperms 

(  Angiosperms 

In  our  study  of  these  groups  we  shall  see  that  in  passing 
from  the  Thallophytes  through  the  various  groups  to  the  Angio- 
sperms we  pass  from  very  simple  forms  to  those  which  are  quite 
complex. 

THALLOPHYTES. 

General  Characteristics.  —  This  group  comprises  those  plants 
which  are  simplest  in  form  and  structure.  They  are  supposed 
also  to  represent  more  or  less  primitive  types.  In  these  the  plant 
body  does  not  show  a  differentiation  into  root,  stem,  and  leaf, 
as  in  the  higher  plants,  and  is  termed  a  thallus,  the  word  thallus 
meaning  a  "  mass  "  of  cells.  The  cells  making  up  a  thallus  are 
all  alike  and  are  not  differentiated  for  special  functions.  How- 
ever, it  must  not  be  thought  that  every  Thallophyte  is  charac- 
terized in  this  way.  Many  of  the  Thallophytes  have  cells  or 
groups  of  cells  which  become  specialized,  i.e.,  set  apart  for  a 
particular  function,  as  for  example  the  reproductive  cells.  We 
see,  therefore,  that  the  word  Thallophyte  is  a  general  term  and 
is  applied  to  many  plants  which  are  not  thallus-bearing,  but 
which  are  really  closely  related  to  the  simpler  forms  to  which 
the  word  Thallophyte  is  strictly  applicable.  When  made  up  of 
a  mass  of  cells  they  may  branch  in  various  ways,  but  the  essential 
structure  remains  more  or  less  uniform  throughout. 

The  Thallophytes  vary  in  size  and  general  appearance  from 
minute,  unicellular  organisms  to  those  which  are  filamentous 
and  delicately  branched,  and  even  becoming  leaf-like  structures, 
attaining  a  length  in  some  of  the  marine  algae  of  a  thousand  feet 


PRINCIPAL  GROUPS  OF  PLANTS.  7 

and  even  more.  Some  of  these  are  more  or  less  complicated  in 
structure. 

The  Thallophytes  are  subdivided  into  two  important  groups, 
as  follows: 

The  Algae,  plants  producing  chlorophyll  or  green  cell-contents, 
and  hence  capable  of  manufacturing  food  from  the  inorganic 
substances  air  and  water. 

The  Fungi,  plants  not  producing  chlorophyll,  and  hence  not 
capable  of  forming  their  own  food,  but  living  upon  dead  or 
living  matter. 

Before  considering  the  Algae  proper  we  will  consider  two 
groups  which  are  very  simple  in  structure  and  whose  method  of 
reproduction  as  well  as  life  history  is  also  very  simple;  namely, 
the  Blue-green  Algae  and  the  Bacteria.  The  Blue-green  Algae  are 
ordinarily  classified  with  the  Algae,  and  the  Bacteria  are  very 
often  grouped  with  the  Fungi.  Owing  to  certain  resemblances 
between  these  two  groups  it  is  convenient  to  arrange  them  to- 
gether under  the  name  Schizophytes,  or  fission  plants. 

SCHIZOPHYTES. 

Characteristics. — The  name  Schizophyta  means  "  fission 
plants,"  and  is  applied  to  this  group  because  the  reproduction  is 
chiefly  by  means  of  the  division  of  the  cells,  which  may  occur 
either  at  the  middle  of  the  cell  and  in  one  direction,  in  which 
case  a  series  of  connected  cells  are  formed,  or  in  two  or  three 
directions,  giving  rise  to  spherical  aggregates  or  colonies.  They 
do  not  usually  contain  chromatophores,  and  the  coloring  sub- 
stance, when  present,  is  either  uniformly  distributed  throughout 
the  cell  or  occurs  on  the  external  surface  of  the  protoplasmic 
content. 

There  are  two  chief  groups:  the  one  corresponds  to  Algae, 
and,  while  they  do  not  contain  a  simple  green  substance,  they  are 
for  the  most  part  of  a  blue-green  color,  although  they  may  assume 
various  shades  of  orange,  yellow,  and  brown,  even  appearing 
chocolate  or  purplish-red  at  times.  The  second  group,  correspond- 
ing to  the  Fungi,  comprises  the  Bacteria  or  Schizomycetes,  which 
are  distinguished  for  the  most  part  by  being  nearly  colorless  and 
only  occasionally  of  a  reddish  or  green  color. 


8  A  TEXT-BOOK  OF  BOTANY. 

SCHIZOPHYCE^;,  OR  FISSION  ALG^E.— This  group  of 
plants,  also  known  as  Cyanophyceee  or  Blue-green  Algae  (Fig.  6), 
are  generally  found  in  more  or  less  stagnant  water  and  are  charac- 
terized by  having  associated  with  the  chlorophyll  a  definite  blue- 
green  principle  known  as  phycocyanin.  However,  many  of  these 
Algae  contain  other  pigments  in  such  quantity  as  to  give  them  dis- 
tinct colors  much  like  those  found  in  the  red  and  brown  Algae,  such 
as  Trichodesmium,  a  filamentous  Alga  giving  the  Red  Sea  its  char- 
acteristic appearance.  Some  of  these  live  at  the  highest  tempera- 
ture known  to  support  life ;  some  developing,  as  Gloeocapsa,  on  the 
sides  of  the  geysers  in  the  Yellowstone  Park.  These  forms  have 
very  wide  habits,  some  living,  as  Stigonema,  in  symbiosis  with 
fungi ;  some,  as  Nostoc,  are  endophytic  in  habit,  living  in  the  de- 
pressions of  various  plants,  and  others,  as  Mastigocoleus,  boring 
into  shells. 

They  are  found  mostly  in  fresh  water,  and  some,  as  Uroglena, 
cause  considerable  trouble  in  public  water  supplies  by  reason  of 
their  breaking  down  the  cell-wall  and  the  liberation  of  a  fetid 
oily  substance. 

While  these  plants  do  not  produce  true  spores,  yet  they  are 
able  to  tide  themselves  over  adverse  conditions  by  producing  rest- 
ing bodies  through  the  formation  of  a  thicker  membrane  and  a 
more  concentrated  cell-content.  In  this  condition  they  are  able  to 
hold  over  for  several  years  and  then  grow  when  the  conditions  of 
temperature,  nutrition,  etc.,  are  suitable  for  their  germination.  As 
a  rule,  they  grow  best  in  shallow,  stagnant  water  with  the  rela- 
tively high  temperature  of  the  summer  months.  When  public 
water  supplies  are  polluted  by  these  blue-green  Algae  it  has  been 
found  that  the  Algae  are  completely  destroyed  by  the  addition  of 
a  very  small  amount  of  copper  sulphate  to  the  reservoir.  As 
small  a  quantity  as  one  part  per  million  is  sufficient  to  accomplish 
this  result,  not  only  killing  the  troublesome  organisms,  but  pre- 
venting their  development  for  some  months  to  come.  A  few  of 
the  common  forms  will  be  considered. 

Gloeocapsa  is  one  of  the  simplest  of  the  Blue-green  Algae 
(Fig.  6),  consisting  of  spheroidal  cells  from  0.0035  to  0.005  mrn. 
in  diameter,  of  a  yellowish  or  brownish-yellow  color,  and  usually 
embedded  in  groups  of  two  or  some  multiple  of  four  in  an  olive- 


PRINCIPAL  GROUPS  OF  PLANTS. 


A  mass  of  cells  after  numer- 
ous divisions,  all  surrounded 
by  a  mucilaginous  envelope. 

GLOEOCAPSA. 


Single  cell  just  after 
division.  The  two 
daughter  cells  re- 
tained in  a  gelatinous 
mass.  Diameter 
about  4  microns. 


A  single  colony. 
Diameter  of  colonies  varying  Single  cell  showing 

from  40  to  290  microns.  spiral  chromatophore. 

Length,  14  to  18  mi- 

UROGLENA     ««* 


Heterocyst  which  divides  the 
filament  into  smaller  filament*. 


Thick-walled  resting  cellt. 


Filamentous  colonies  coiled 
within  the  masses  of  jelly 


Spherical  gelatinous  masses 
as  found  floating  in /ponds. 
About  twice  natural  size. 


Part  of  a  single  filament 
Diameter,  4  to  12  microns. 


u 

OSCILLATORIA 


Diameter  of  filaments, 

5  to  50  microns. 


Decaying  cell 
unctioning  as  a  heterocyst. 


Filaments,  about  10  to  60 
in  diameter. 


LYNGBYA 


FIG.  6.     Forms    of    Cyanophyceae    or    Blue-Green    Algae. — Adapted    from    Engler    and 
Prantl  and  Somewhat  modified  by  Lobeck. 


io  A  TEXT-BOOK  OF  BOTANY. 

brown  gelatinous  stratum,  this  arrangement  due  to  the  cell  divid- 
ing in  all  directions.  They  occur  on  moist  earth,  stones,  wharf 
pilings,  and  even  on  window  panes  of  greenhouses,  thus  being 
distributed  in  both  fresh-  and  salt-water  regions.  They  some- 
times form  a  kind  of  crustaceous  stratum,  and  sometimes  soft, 
slimy  masses  sufficiently  abundant  that  they  can  be  stripped  by  the 
handful  from  dripping,  partially  shaded  rocks.  Owing  to  the 
variation  in  color  and  general  habit  of  the  plant  a  great  many 
species  have  been  described,  but  up  to  the  present  time  about  60 
have  been  sharply  distinguished. 

Oscillatoria,  formerly  known  as  Oscillaria,  is  the  name  applied 
to  a  simple  filamentous  blue-green  alga  (Fig.  6)  that  is  char- 
acterized by  movement  from  side  to  side  as  in  a  pendulum,  due, 
as  has  been  suggested,  to  the  movement  of  spiral  masses  of  proto- 
plasm extending  from  cell  to  cell.  These  filaments  consist  of  a 
series  of  disk-shaped  cells  like  a  pile  of  coins  placed  side  by  side, 
the  end  cell  being  rounded  off  and  more  or  less  convex.  The  con- 
tents are  made  up  of  a  finely  granular  substance  differentiated 
into  two  areas,  a  dark  central  nuclear  portion,  and  a  peripheral 
holding  the  pigment,  which  may  vary  from  a  bluish-green  to  dark 
olive-green  or  even  red  sufficiently  intense  to  give  the  water  a 
red  color.  The  filaments  vary  from  o.ooi  to  0.005  mm.  in  diame- 
ter, though  they  may  attain  a  size  of  0.050  mm. 

Oscillatoria  is  usually  found  on  wet,  marshy  grounds,  in 
ditches  among  decayed  vegetable  matter,  on  wood  subject  to  hot 
waste  from  steam  engines,  around  pumps  and  cisterns,  and  in 
greenhouses.  It  occurs  in  fresh  and  salt  water. 

Lyngbya  somewhat  resembles  Oscillatoria,  but  does  not  show 
any  oscillations  and  the  filaments  are  each  provided  with  a  dis- 
tinct sheath  (Fig.  6).  It  forms  late  in  the  summer  in  large  tufts. 
It  is  of  a  bluish-green  color,  forms  long  filaments,  occurring  in 
the  late  summer  upon  Zostera  and  other  Algae.  The  groups  are 
large  and  characteristic  and  have  been  given  the  common  name 
Mermaid's  Hair.  The  cells  are  about  0.030  mm.  in  diameter. 

Uroglena  is  a  form  which  is  more  or  less  oval  or  pear-shaped, 
about  0.014  to  0.018  mm.  in  length,  and  extended  into  a  stalk  below, 
the  upper  end  being  provided  with  two  unequal  cilia  (Fig.  6). 
The  wall  secretes  a  large  amount  of  mucilage.  The  organisms 


PRINCIPAL  GROUPS  OF  PLANTS.       n 

arrange  themselves  in  a  radiating  sphere,  with  the  cilia  at  the 
periphery.  Each  cell  of  the  colony  contains  a  more  or  less  spiral, 
yellowish  chromatophore,  bearing  a  reddish  spot  at  one  end,  a 
nucleus  at  the  centre,  and  a  few  vacuoles.  The  cells  secrete  a 
large  quantity  of  oil,  which  is  of  an  unpleasant,  fish-like  odor,  and 
is  due  either  to  the  decay  or  breaking  up  of  the  cells  by  mechanical 
means.  This  breaking  up  of  the  cells  is  the  cause  of  the  disagree- 
able odor  occasionally  found  in  public  water  supplies.  Uroglena 
is  found  in  New  England  and  has  been  reported  as  far  west  as 
Indiana,  and  is  probably  rather  widely  distributed  in  the  United 
States.  It  seems  to  thrive  best  in  cold  temperatures,  usually 
occurring  in  greatest  numbers  when  the  water  is  frozen  over. 
It  multiplies  by  cell  division,  which  takes  place  when  the  colony 
becomes  rather  large.  It  also  produces  resting  spores  which 
enable  the  organism  to  survive  conditions  which  would  otherwise 
exterminate  it. 

A  closely  related  organism,  Synura,  is  responsible  for  the  ripe 
cucumber  odor  which  was  formerly  thought  to  be  caused  by 
fresh- water  sponges'. 

Nostoc,  a  form  occurring  in  filaments  like  a  string  of  pearls,  is 
made  up  of  spherical  or  elliptical  cells,  the  whole  being  surrounded 
by  a  thick,  mucilaginous  membrane  (Fig.  6).  Usually  one  finds  a 
number  of  these  filaments  growing  together  in  a  mass  which  can 
be  seen  by  the  naked  eye  floating  in  the  water.  These  masses 
vary  from  globular  to  sub-globular,  are  irregularly  divided  or 
occur  in  definitely  expanded  groups.  These  forms  are  marked  by 
having  two  kinds  of  cells,  the  one  filled  with  a  granular  proto- 
plasmic content,  the  other  being  free  from  protoplasm  and  some- 
what larger  than  the  other  cells.  These  latter  are  fewer  in  number 
and  are  called  "  heterocysts,"  which  means  simply  "  other  cells." 
At  these  latter  cells  the  filaments  separate,  and  thus  many  new 
colonies  are  formed.  Nostoc  is  mostly  of  an  olive-green  color, 
but  may  be  dark  bluish-green,  dark  brown,  or  light  yellow  or  even 
colorless.  It  occurs  mostly  in  fresh-water  ponds,  seldom  in 
brackish  water,  being  found  on  damp  rocks,  on  mosses  and  more 
or  less  submerged  plants,  and  variously  in  limestone  springs  or  wet 
calcareous  rocks  or  on  aluminous  soil.  The  colonies  vary  greatly 
in  size  and  color,  and  while  some  of  them  may  be  of  microscopic 


12  A  TEXT-BOOK  OF  BOTANY. 

size  at  one  period,  later  they  may  be  as  large  as  peas  or  cherries. 
Owing  to  their  variation  in  appearance  in  different  seasons  various 
names  have  been  given  to  the  same  form  by  different  investigators. 
They  are  also  associated  with  lichens.  According  to  systematists, 
the  forms  of  Nostoc  are  arranged  according  to  their  aquatic  or 
terrestrial  habits. 

SCHIZOMYCETES,  OR  BACTERIA.— The  Bacteria,  or 
Fission  Fungi,  occupy  rather  an  anomalous  position,  some  writers 
classifying  them  with  Fungi  and  some  with  Algae.  They  are  i- 
celled  plants,  microscopic  in  size,  and  of  various  shape.  The  con- 
tents consist  of  protoplasm  and  a  central  body  in  some  cases,  which 
is  looked  upon  as  a  rudimentary  nucleus.  They  are  more  or  less 
colorless,  but  sometimes  produce  a  distinct  pigment  called  bacterio- 
purpurin  which  is  rose-red  or  violet,  and  occasionally  a  chlorophyll- 
green  color  substance.  They  are  capable  of  multiplying  by  division 
in  one,  two,  or  three  directions,  and  under  favorable  conditions  in- 
crease very  rapidly  in  number.  The  wall  is  more  or  less  albumin- 
ous in  character,  in  this  "respect  resembling  the  wall  of  the  animal 
cell,  and  is  provided  with  one  or  more  cilia,  or  flagella,  the  number 
and  position  of  which  have  been  used  as  a  basis  of  classification. 
Sometimes  the  walls  of  the  Cells  become  mucilaginous,  so  that  the 
,bacteria  hold  together,  forming  a  mass  known  as  a  zoogloea. 
Bacteria  may  form  resting  spores  which  arise  in  two  ways.  In 
one  case  the  contents  round  off  and  take  on  a  membrane  forming 
a  so-called  ENDOSPORE  ;  in  the  other  case  the  plant  body  is  trans- 
formed directly  into  a  spore  known  as  an  ARTHROSPORE,  as  in 
some  of  the  Blue-green  Algae.  This  body  is  not  strictly  a  spore, 
but  is  in  the  nature  of  a  resting  cell  (Fig.  7).  Two  classes  of 
bacteria  are  frequently  distinguished,  as  follows :  Aerobic,  or 
those  which  require  oxygen  for  their  development  and  conse- 
quently grow  best  when  they  have  access  to  air  or  oxygen;  and 
anaerobic,  or  those  whose  development  is  accelerated  under  re- 
verse conditions,  as  in  underlying  tissues  or  in  the  interior  of 
cultures. 

Occurrence. — Bacteria  occur  everywhere  in  nature,  and  play 
a  most  important  part  in  decay  and  putrefaction,  in  that  they 
change  dead  animal  and  plant  tissues  back  again  into  simple  inor- 
ganic substances,  as  carbon  dioxide,  hydrogen,  water,  ammonia, 


PRINCIPAL  GROUPS  OF  PLANTS.  13 

etc.  They  serve  a  useful  purpose  in  many  technical  operations,  as 
in  the  making  of  cheese,  acetic  acid,  fermentation  of  tobacco, 
curing  of  vanilla  and  many  vegetable  drugs,  and  in  soil  nitrification, 
helping  to  change  ammonia  into  nitrates — one  of  the  sources  of 
the  nitrogen  used  by  plants.  Many  of  them  are  disease-producing, 
or  pathogenic,  and  are  the  cause  of  a  number  of  infectious  dis- 
eases in  man  and  the  lower  animals,  and  plants  as  well.  They  are 


FIG.  7.  Bacillus  subtilis  (hay  bacillus),  a,  Small  rod-like  organisms  such  as  are 
found  in  an  infusion  of  hay,  or  bouillon;  b,  zoogloea  or  mass  of  bacilli  forming  the  "skin" 
on  the  surface  of  infusions;  c,  chains  of  organisms  forming  spores;  d,  individual  bacilli 
showing  flagella,  which  are  only  seen  after  staining. — After  Migula. 

injurious  in  two  ways :  in  one  case  they  consume  the  tissues  of  the 
host,  as  in  tuberculosis,  and  in  the  other  they  produce  powerful 
poisonous  substances,  or  toxins,  as  in  diphtheria. 

Glasses  of  Bacteria. — In  order  to  study  Bacteria  they  are 
grown  upon  nutrient  media,  such  as  sterile  bouillon,  potato,  milk, 
etc.  They  are  divided  into  a  number  of  classes,  depending  for 
the  most  part  on  the  shape  of  the  cell:  (i)  The  Sphserobacteria, 
or  Cocci,  are  those  whose  cells  are  spherical  or  spheroid,  and  in 


I4  A  TEXT-BOOK  OF  BOTANY. 

which  division  takes  place  in  one,  two,  or  three  directions  of  space. 
Very  few  of  this  group  are  provided  with  cilia.  According  to  the 
number  of  cells  in  a  colony  they  are  distinguished  as  Micrococci, 
Diplococci,  etc.  (2)  Bacteria  proper  are  elongated,  rod-shaped 
organisms  in  which  division  occurs  in  only  one  direction,  namely, 
transversely  to  the  long  axis,  and  only  after  a  preliminary  elon- 
gation of  the  bacterium.  The  Bacteria  are  subdivided  into  two 
important  groups,  namely,  Bacterium  and  Bacillus.  The  Bacilli 
are  motile  organisms  and  produce  endospores  (Fig.  7),  whereas 
the  Bacteria  are  non-motile  and  do  not  usually  produce  endospores. 
(3)  Spiral  bacteria  constitute  the  third  principal  group  and  are 
characterized  by  the  cells  being  spirally  coiled.  Division  is  in 
only  one  direction.  These  bacteria  are  usually  motile,  and  seldom 
produce  endospores.  (4)  There  is  another  important  group 
which  includes  the  Sulphur  Bacteria,  of  which  the  most  common 
one  is  Beggiatoa.  These  occur  in  long  threads,  and  move  in  an 
undulating  manner  much  like  Oscillaria,  one  of  the  Blue-green 
Algae.  They  are  found  in  sulphur  waters,  as  in  sulphur  springs, 
and  contain  sulphur  granules. 

Bacteriological  Technique. — Principally  because  of  the 
minuteness  in  size  of  micro-organisms  a  different  technique  is 
required  in  their  study  from  that  required  in  the  study  of  the 
higher  plants.  In  the  first  place  it  is  difficult  to  isolate  them 
so  as  to  be  able  to  study  individual  forms.  Another  difficulty  is 
to  prevent  contamination  after  they  are  isolated.  And  even 
though  a  pure  culture  is  obtained  it  is  difficult  on  purely  morpho- 
logical grounds  to  differentiate  the  various  forms,  as  they  are  all 
so  much  alike. 

I.  While  it  is  comparatively  easy  to  prepare  a  sterile  solution, — 
that  is,  one  in  which  all  life  is  absent, — it  is  very  difficult  to  prevent 
subsequent  contamination  under  ordinary  conditions.  Even  when 
a  cork-  or  glass-stoppered  bottle  for  keeping  liquids  is  used  it  is 
difficult  to  prevent  the  entrance  into  and  development  of  micro- 
organisms in  the  liquids.  The  use  of  stoppers  consisting  of  plugs 
of  absorbent  cotton  was  first  suggested  by  Schroeder  and  von 
Dusch  in  1854.  They  found  that  if  flasks  containing  liquids, 
which  under  ordinary  conditions  were  likely  to  decompose,  as 
beef  broth,  etc.,  were  stoppered  with  plugs  of  absorbent  cotton 


PRINCIPAL  GROUPS  OF  PLANTS.  15 

and    the    liquid    then    boiled    for    some    time    it    would    keep 
indefinitely.' 

II.  It  remained   for  Koch  and   Pasteur  to  show   what  took 
place  in  the  boiling  of  the  liquid,  who  at  the  same  time  developed 
the  principles   of   sterilization   in   bacteriological   work.      These 
authors  discovered  that  micro-organisms  have  two  stages  of  de- 
velopment, one  of  which  is  active  and  the  other  resting,  the  latter 
being  known  as  the  egg  or  spore  condition.    They  found  that  the 
organisms  in  the  active  condition  were  completely  destroyed  on 
heating  the  solution  containing  them  for  30  minutes  at  100°  C. 
If  this  solution  was  allowed  to  stand   for  24  hours  or  longer 
there  would  be  evidences  of  decomposition,  which  was  due  to  the 
fact  that  the  spores  representing  the  resting  stage  of  the  organ- 
isms  were  unaffected  by  the  first  heating  and   developed   into 
the  active  stage.     As  a  result  of  further  experiments  they  found 
that   if   the    solution   were   heated   on    the    second    day    for   30 
minutes  at  a  temperature  of  100°  C.  the  second  growth  of  organ- 
isms was  destroyed,  but  it  was  found  that  the  solution  might  still 
undergo  decomposition  in  the  course  of  time,  owing  to  the  later 
development  of  a  few  remaining  spores.    It  was,  however,  found 
that  heating  the  liquid  again  on  the  third  day  was  sufficient  to 
kill  all  of  the  spores  as  well  as  the  organisms  in  the  active  stage. 
By    repeating    these    experiments    the    authors    confirmed    theii 
observations  and  established  the  process  known  as  discontinuous 
sterilization,  which  simply  means  that  if  a  solution  of  a  putrescent 
or  fermentative  substance  is  heated  on  three  consecutive  days  for 
30  minutes  at  a  temperature  of  100°  C.,  the  flask  or  bottle  being 
stoppered  with  absorbent  cotton,  it  will  keep  indefinitely.    Instead 
of  using  a  plug  of  absorbent  cotton  the  neck  of  the  flask  can  be 
drawn  out  into  a  narrow  tube  and  directed  downwards  (see  Re- 
agents).   The  time  required  for  producing  a  sterile  solution, — that 
is,  one  free  from  micro-organisms  or  their  spores, — can,  however, 
be  much  reduced  by  increasing  the  temperature,  or  pressure,  or 
both.     By  use  of  the  autoclave,  in  which  the  pressure  can  be 
increased  from  10  to  20  pounds,  sterilization  can  be  accomplished 
in  30  minutes  by  using  a  temperature  of  110°  C. 

III.  As  already  indicated,  one  of  the  greatest  difficulties  is  to 
isolate  the  organisms.      In   a   cubic   centimetre   of   water  there 


16  A  TEXT-BOOK  OF  BOTANY. 

may  be  a  million  organisms  representing  various  groups  of  bac- 
teria. In  trying  to  solve  the  problem  of  their  separation  it 
occurred  to  Koch  that  if  he  could  secure  a  medium  which  was 
solid  at  the  ordinary  temperature  and  liquid  at  a  slightly  higher 
temperature,  he  could  mix  a  certain  quantity  of  liquid  containing 
micro-organisms  with  the  medium  in  a  sterile  condition,  and  then 
by  solidifying  the  mixture  the  organisms  would  be  fixed,  and 
thus  from  each  organism  a  colony  would  be  developed  which 
could  be  isolated  and  further  studied.  We  are  indebted  to  Koch 
for  the  use  of  solid  culture  media  like  nutrient  gelatin  and 
nutrient  agar  in  the  study  of  these  organisms. 

IV.  The  application  of  stains  for  differentiating  the  various 
organisms  was  introduced  by  Weigert  in  1877.  Staining  is  of  use 
in  the  determination  of  the  number  of  flagella  of  certain  organisms, 
in  the  study  of  spores,  and  the  identification  of  certain  pathogenic 
organisms,  which  occur  in  mucus  and  pus,  as  tubercle  bacilli, 
etc.  Gram's  method  of  staining  is  of  great  use  in  differentiating 
many  pathogenic  as  well  as  non-pathogenic  organisms,  and  is  of 
importance  in  classifying  bacteria. 

ALG.E. 

Characteristics. — Algae  are  characterized  by  their  habit  of 
living  in  water  or  in  moist  places.  They  vary  from  simple,  i -celled 
microscopic  forms  to  those  of  great  size  like  the  sea-weeds.  In 
the  various  types,  however,  the  cells  show  little  variation  in  shape. 
All  the  Algae  contain  more  or  less  of  a  green  coloring  matter,  even 
though  it  may  be  concealed  by  other  pigments  of  a  blue  (as  in 
Schizophyta),  brown,  or  reddish  color.  The  possession  of  this 
green  cell-content  or  chlorophyll  enables  the  Algae,  in  the  presence 
of  sunlight,  to  manufacture  food  substances  from  simple  materials 
like  carbon  dioxide  and  water. 

The  occurrence  of  chlorophyll  can  be  readily  demonstrated  by 
extracting  it  with  95  per  cent,  alcohol.  Even  in  the  most  delicate 
of  the  red  Algae  it  can  be  shown  by  placing  the  fresh  material  in 
a  strong  solution  of  common  salt  and  afterwards  extracting  the 
chlorophyll  with  alcohol,  the  other  pigments  being  unaffected. 

Algae  are  sometimes  grouped  as  Fresh- Water  Algae,  includ- 


PRINCIPAL  GROUPS  OF  PLANTS.  17 

ing  most  of  the  Green  Algae,  and  the  Marine  Algae  or  Sea-weeds, 
including  most  of  the  brown  and  red  forms. 

Algae  are  classified  in  three  natural  groups,  not  only  on  account 
of  color  differences,  but  because  of  certain  corresponding  struct- 
ural relationships,  thus : 

Chlorophyceae  (Green  Algae). 
Phaeophyceae  (Brown  Algae). 
Rhodophyceae  (Red  Algae). 

Arranging  the  Algae  in  this  way  provides  the  simplest  classi- 
fication. But  in  addition  to  these  groups  there  is  another  some 
what  isolated  group  that  will  be  taken  up  first  before  the  Chloro- 
phyceae, — namely,  the  Conjugatae.  These  are  Green  Algae  con- 
sisting of  either  single  cells  or  a  chain  of  cells  united  into  threads 
and  further  characterized  by  dividing  always  in  the  one  direction 
so  that  a  filament  results.  They  furthermore  do  not  produce 
zoospores,  but  produce  zygospores  as  a  result  of  a  union  of  two 
similar  or  only  slightly  different  cells.  After  a  period  of  rest 
they  break  from  the  outer  membrane  and  develop  directly  into  new 
vegetable  cells.  To  this  class  the  Desmids  and  Spirogyra  belong. 

The  Desmids  are  unicellular  Algae,  varying  from  torpedo- 
shaped  to  variously  branched  forms,  occurring  even  in  chains. 
The  protoplast  is  usually  separated  at  or  near  the  middle,  where 
the  nucleus  is  located,  dividing  the  cell  into  two  symmetrical  por- 
tions (Fig.  8,  E).  In  the  protoplast  is  a  more  or  less  complex 
chromatophore,  through  the  center  of  which  are  distributed  a 
number  of  globular  pyrenoids.  The  latter  are  distinct  structures 
embedded  in  the  chromatophores  of  Green  Algae  and  consist  of 
a  central  protein  substance  surrounded  by  a  number  of  starch 
grains,  and,  therefore,  give  a  purple  reaction  with  iodine.  Owing 
to  the  fact  that  the  Desmids  are  motile  they  were  formerly  con- 
sidered to  be  members  of  the  animal  kingdom.  The  movement  is 
slow  and  steady  and  largely  influenced  by  the  light.  There  is  also  a 
circulatory  movement  frequently  observed  in  the  contents  of 
active  living  material.  In  addition,  there  is  almost  always  observ- 
able at  the  ends  a  well-defined  spherical  vacuole  containing 
numerous  small  crystals  of  calcium  sulphate  which  exhibit  a 
dancing  movement  due  to  surface  tension  and  is  known  as  molec- 


iS 


A  TEXT-BOOK  OF  BOTANY. 


ular  or  Brownian  movement.  Reproduction  is  either  by  simple 
division  or  by  the  union  of  two  Desmids.  In  the  latter  case  the 
contents  of  each  flow  together  into  a  connecting  tube  formed  by 
the  union  of  the  two  Desmids,  the  resultant  mass  rounding  off  to 
form  a  zygospore. 


FIG.  8.  Forms  of  Desmids  in  longitudinal  view  and  transverse  section.  A,  Meso- 
tcenium  Braunii;  B,  Ancylonema  Nordenskioldii;  C,  Penium  digitus;  D,  Cylindrocystis  crassa; 
E,  Closterium  moniliferum;  F,  Spirotcenia  muscicola;  G,  Pleurotcenium  trabecula;  H,  a  Docid- 
ium  baculum;  Ha',  D.  dilatatum. — From  Wille  in  Engler  and  Piantl's  "Die  Naturlichen 
Pflanzenfamilien." 

Spirogyra. — Another  one  of  the  common  Green  Algae  is 
Spirogyra  (Fig.  9),  one  of  the  pond-scums,  which  in  the  spring 
forms  floating  green  masses  on  ponds  and  shallow  water.  The 
plant-body  consists  of  a  chain  of  cylindrical  cells  forming  long 
threads  or  filaments.  The  transverse  walls  are  sometimes  pecu- 
liarly thickened.  The  chromatophores  occur  in  one  or  more  spiral 


PRINCIPAL  GROUPS  OF  PLANTS.  19 

bands  (Fig.  9,  //),  which  extend  from  one  end  of  the  cell  to  the 
other.  In  these  bands  are  embedded  protein  bodies  known  as 
pyrenoids.  The  nucleus  lies  in  the  centre  of  the  cell  and  is  con- 
nected with  the  cytoplasmic  layer  lining  the  walls  of  the  cell  by 
delicate  threads  of  cytoplasm. 

Spirogyra  may  be  propagated  vegetatively  by  one  or  more 
cells  of  a  filament  breaking  off  and  forming  new  individuals  by 


FIG.  9.  II.  Spirogyra  stictica,  showing  parts  of  two  filaments  with  band-like  chroma- 
tophores  (chloroplasts),  in  which  are  embedded  spherical  pyrenoids.  Nuclei  are  shown 
in  some  of  the  cells  with  delicate  threads  of  cytoplasm  radiating  from  them.  Two  of  the 
cells  (a,  a)  of  the  adjoining  filaments  (A,  B)  are  beginning  conjugation.  I,  5.  Heeriana, 
showing  different  stages  of  conjugation.  In  the  upper  cells,  the  contents  have  rounded  off 
previous  to  the  rupture  of  the  adjoining  walls  of  the  two  filaments.  The  two  middle  cells 
show  the  contents  passing  from  one  cell  into  the  opposite  cell.  In  the  lower  cell  to  the 
right  the  zygospore  is  shown. — After  De  Bary. 

cell  division.  The  plant  is  also  reproduced  by  means  of  zygo- 
spores,  as  follows:  The  cells  of  two  adjoining  filaments  each 
send  out  processes  (Fig.  9,  //,  a,  a),  which  meet;  the  end  walls 
are  absorbed,  forming  a  tube  through  which  the  contents  from  one 
cell  pass  over  into  the  other  (Fig.  9,  /)  ;  the  contents  of  the  two 
cells  then  fuse,  after  which  the  mass  becomes  surrounded  by  a 
cellulose  wall.  The  spore  thus  formed  may  remain  dormant  over 
winter,  and  the  following  spring  germinate  and  form  a  new  Spyro- 


20  A  TEXT-BOOK  OF  BOTANY. 

gyra  filament  or  plant.  This  method  of  reproduction  is  known 
as  CONJUGATION,  and  the  zygospore  is  called  a  resting  spore.  It 
should  be  explained  that  certain  cells,  as  well  as  spores,  may  lie 
dormant  for  a  period,  as  during  the  winter  season  or  at  other 
times,  when  the  conditions  are  unfavorable  to  growth,  and  then 
renew  their  activities,  these  being  known  as  "  resting  cells." 

CHLOROPHYCE^. — The  Chlorophyceae,  or  Green  Algae,  are  dis- 
tinguished by  usually  having  a  green  color,  due  to  chlorophyll,  and 
by  having  no  other  pigment.  The  cells  contain  one  or  more  nuclei. 
They  are  either  unicellular  or  made  up  of  many  cells  forming  fila- 
ments or  flat  sheets.  They  occur  either  singly  as  simple  cells  or 
in  groups  representing  a  single  individual  or  a  colony.  They  are 
found  mostly  in  fresh  or  salt  water,  usually  being  microscopic 
in  size  so  as  not  to  be  noticed,  but  often  attracting  attention  when 
they  occur  in  sufficient  quantity  to  form  a  scum  on  the  surface. 
The  reproduction  is  mostly  by  ciliated  cells  called  zoospores  or 
swarm  spores.  Reproduction  also  takes  place  by  the  union  of 
the  zoospores  and  through  the  fertilization  of  egg  cells.  The 
sexual  spore  resulting  from  this  union  of  like  cells  (forming 
a  zygospore)  or  of  unlike  cells  (forming  an  oospore)  seldom 
develops  immediately,  but  usually  undergoes  a  resting  period  be- 
fore growth  is  continued 

Protococcus. — One  of  the  commonest  of  the  Green  Algae 
as  well  as  one  of  the  simplest  is  Protococcus  (Pleurococcus)  vul- 
garis  (Fig.  10).  It  occurs  as  a  green  coating,  in  both  winter  and 
summer,  on  the  moist  bark  of  trees,  moist  ground,  and  stone 
walls,  and  is  a  component  of  some  lichens.  The  plant  is  i- 
celled,  more  or  less  spherical,  and  at  one  stage  contains  a  number 
of  chlorophyll  grains  which  finally  unite  to  form  a  single  plate 
which  lies  against  the  wall  and  is  known  as  a  CHROMATOPHORE. 
Besides  it  contains  a  considerable  amount  of  oil.  An  allied 
species  (Protococcus  viridis)  contains  the  sugar  erythrite.  The 
plant  usually  reproduces  by  simple  division, — that  is,  one  cell 
or  plant  divides  to  form  two.  The  divisions  may  continue  by  the 
production  of  another  cross  wall,  so  that  four  cells  result.  Under 
favorable  conditions,  division  may  take  place  by  the  formation 
of  still  another  wall  at  right  angles  to  the  other  two.  In  this 
way  two,  four  and  finally  eight  individuals  arise  which  adhere 


PRINCIPAL  GROUPS  OF  PLANTS.  21 

more  or  less  to  one  another,  thus  forming  colonies.  The  number 
of  individuals  in  a  colony  depends  upon  the  number  of  indi- 
viduals in  the  colony  when  division  begins  and  the  extent  to 
which  division  is  carried.  Thus  if  there  were  four  cells  in  a 
colony  to  begin  with  and  division  took  place  in  three  planes,  there 
would  be  thirty- two  cells  in  the  colony  at  the  end  of  the  period. 
The  development  of  the  green  coating  on  the  barks  of  trees, 
due  to  the  growth  of  Protococcus  and  the  protonema  of  mosses, 
is  usually  thought  to  be  more  pronounced  on  the  north  side.  This, 
however,  is  a  slightly  false  notion.  The  fact  which  determines 
the  position  of  these  plants  is  the  quantity  of  moisture  available. 
The  south  and  southwest  sides  of  trees  in  the  northern  hemisphere 
are  exposed  to  more  light  and  heat  and  consequently  are  apt  to  be 
drier,  with  the  result  that  they  are  rarely  covered  with  coatings  of 


FIG.   10.     Protococcus  vulgaris.     Different  stages  of  division  of  the  cell. — After  Wille. 

Protococcus  and  mosses.  The  under  side  of  slanting  trees  is  a 
very  favorable  place,  as  are  also  the  lower  slanting  surfaces  near 
the  ground  of  large  upright  trees,  because  in  these  places  the 
water  is  more  likely  to  be  conserved.  A  careful  investigation  by 
Kraemer  showed  a  more  abundant  growth  of  green  plants  on  the 
east  and  southeast  exposure,  although  the  north  side  of  many  trees 
showed  good  growth  also. 

Volvox  occurs  widely  distributed  throughout  the  United 
States  in  ponds  and  pools  of  fresh  water.  It  is  most  abundant 
in  warm  weather,  but  also  found  in  midwinter.  It  appears  as  a 
minute  spherical  colony  about  y2  mm.  in  diameter,  made  up  of 
numerous  cells,  the  number  ranging  from  several  hundred  to 
many  thousand  (Fig.  11).  The  cells  at  the  periphery  are  pro- 
vided with  cilia,  so  that  the  colony  rolls  slowly  through  the 
water.  Each  cell  contains  a  chloroplastid  in  which  starch  granules 
and  often  a  red  pigment  spot  are  present.  The  asexual  reproduc- 


22  A  TEXT-BOOK  OF  BOTANY. 

tion  is  through  the  formation  of  daughter  colonies  within  the 
mother  colony,  and  these  after  a  time  develop  motile  cells  like  the 
parent,  which  swim  about  and  finally  escape.  A  sexual  method 
of  reproduction  also  occurs  in  which  there  is  a  union  of  cells 
within  the  spheres,  the  resulting  cells  after  germination  forming 
swarm  spores  that  cling  together  to  form  a  new  colony. 

Hydrodictyon,  or  Water  Net,  is  a  form  often  very  abundant 
in  sluggish  and  stagnant  waters.  It  consists  of  a  number  of  cells 
forming  a  net,  the  meshes  of  which  are  usually  hexagonal  or 
pentagonal  in  shape,  depending  on  the  number  of  cells  outlining 
them  (Fig.  n).  The  cells  are  all  alike,  cylindrical  in  form, 
attaining  sometimes  a  length  of  i  cm.,  and  usually  contain  a 
number  of  nuclei.  The  green  chromatophore  occurs  in.  a  plate 
at  the  periphery  of  the  cell  and  usually  contains  numerous 
pyrenoids. 

The  asexual  reproduction  is  by  means  of  zoospores  which 
are  formed  simultaneously  in  large  numbers,  sometimes  number- 
ing many  thousands  in  each  cell.  These '  zoospores  as  formed 
inside  of  the  mother  cell  show  more  or  less  definite  movement 
and  arrange  themselves  finally  to  form  a  new  net.  The  sexual 
reproduction  is  characterized  by  several  stages,  (i)  Some  of  the 
zoospores  are  liberated  through  a  pore  in  the  cell- wall  of  the 
mother  cell  and  after  swimming  around  for  some  time  pairs  of 
them  unite,  forming  zygospores.  (2)  After  a  resting  period  each 
zygospore  develops  2  to  5  zoospores,  which  escape  into  the  water 
and  develop  into  irregular,  sharp-angled  cells,  called  polyhedra, 
which  persist  through  the  winter.  (3)  When  these  polyhedra 
develop,  small  zoospores  are  again  formed,  and  these  arrange 
themselves  to  form  a  net  inside  of  the  polyhedron,  which  then 
escapes  and  increases  in  size. 

Vaucheria  (Fig.  12)  is  another  common  green  alga  which 
may  also  be  selected  as  showing  the  habits  of  this  group  of 
plants.  The  plant  has  a  branching  thallus  and  lives  in  shallow 
water  or  on  moist  earth,  being  attached  to  the  substratum  by 
means  of  delicate  root-like  processes  sometimes  spoken  of  as 
rhizoids  (Fig.  12,  w).  In  the  thin  layer  of  protoplasm  lying  near 
the  wall  are  numerous  nuclei  and  small  oval  chromatophores. 


PRINCIPAL  GROUPS  OF  PLANTS. 


Single 
polyhedron. 


Net  developing 
inside  of  polyliedro 


OEDOGONIUM. 


Three  stages  in  sexual  reproduction. 

HYDRODICTYOX 


ULVA 


Mature  Colony— Diameter  2  mm. 

A.  Egg  cell,  before  fertilization. 

B.  Oospore. 

C.  Daughter  colony 


VOL VOX 


FIG.   II.     Forms   of   Chlorophyceas   or   Green   Algae. — All   adapted  from    Engler  and 
Prantl  except  Ulva.     Drawn  by  A.  K.  Lobeck. 


24  A  TEXT-BOOK  OF  BOTANY. 

Numerous  oil  globules  are  also  found  in  the  protoplasm,  and  cal- 
cium oxalate  crystals  may  occur  in  the 'cell-sap. 

Vaucheria  furnishes  an  example  of  a  plant  whose  interior  is 
not  segmented  by  cell-walls.  In  other  words,  the  cavity  within 
the  outer  or  enclosing  membrane  is  continuous,  and  such  a  plant 
is  said  to  be  coenocytic, — i.e.,  like  a  syphon.  But  it  should  be  borne 
in  mind  that  the  plant  contains  a  great  many  nuclei,  and,  as  we 
have  seen  (page  2),  a  nucleus  with  its  associated  cytoplasm 


FlG.  12.  Vaucheria  sessilis.  A,  sporangium  from  which  the  multiciliate  zoospore  is 
escaping;  B,  resting  zoospore;  C,  D,  germinating  zoospores  with  growing  point  (s);  E, 
plant  showing  root-like  organ  of  attachment  (w),  spore  from  which  the  plant  is  developing 
(sp);  F,  showing  in  addition  two  oogonia  (og)  and  an  antheridium  (h). — After  Sachs. 

constitutes  a  unit  of  work.  Hence  such  a  plant  as  Vaucheria  is  in 
a  certain  sense  equivalent  to  a  plant  having  as  many  uninucleate 
cells  as  it  has  nuclei.  It  would  probably  be  better  to  call  such  a 
plant  multinucleate  rather  than  unicellular. 

Reproduction  by  means  of  asexual  spores  is  brought  about  as 
follows  (Fig.  12,  A)  :  A  cross  wall  is  formed  near  the  end  of  one 
of  the  branches,  the  end  portion  constituting  a  sporangium.  The 
contents,  including  numerous  nuclei,  group  themselves  into  one 
large  zoospore,  which  escapes  through  an  opening  in  the  sporan- 


PRINCIPAL  GROUPS  OF  PLANTS.  25 

gial  wall,  and  after  swimming  about  for  a  time  comes  to  rest 
and  germinates,  giving  rise  to  a  new  plant  (Fig.  12,  C,  D).  This 
large  zoospore  is  multinucleate  and  multiciliate,  there  being  two 
cilia  for  each  nucleus,  and  by  some  botanists  is  considered  to  be 
an  aggregation  of  numerous  biciliate  zoospores.  It  is  also  of 
interest  to  note  that  the  zoospores  of  Vaucheria  appear  to  arise  by 
a  grouping  of  the  cytoplasm  and  the  nuclei  already  existing  in  the 
sporangium  rather  than  by  repeated  divisions  of  a  single  nucleus. 

Another  method  of  reproduction  in  Vaucheria  (Fig.  12,  F) 
is  that  by  means  of  oospores,  or  spores  formed  by  the  union  of 
egg  and  sperm  cells.  Two  special  branches  are  formed  on  the 
thallus  as  short  side  shoots.  One  of  these  branches,  known  as 
the  oogonium  (Fig.  12,  og),  is  somewhat  egg-shaped  and  sepa- 
rated from  the  thallus  by  means  of  a  cross  wall.  It  contains  a 
great  many  chromatophores  and  considerable  oil,  and  has  a  com- 
paratively thick  wall.  The  apex  is  somewhat  beaked  and  con- 
tains colorless  protoplasm.  The  second  branch,  which  is  known 
as  an  antheridium  (Fig.  12,  h),  is  smaller,  somewhat  cylindrical 
and  curved  towards  the  oogonium.  It  is  also  cut  off  from  the 
thallus  by  means  of  a  cross  wall.  The  antheridium  contains  very 
little  chlorophyll,  but  a  great  many  sperm  cells.  These  are  oval 
or  egg-shaped  and  have  two  cilia,  one  at  each  end.  The  sperms 
escape  from  the  apex  of  the  antheridium  and  enter  an  opening 
at  the  apex  of  the  oogonium,  one  of  them  uniting  with  the  egg 
cell,  which  then  develops  a  thick  membrane,  the  resulting  oospore 
being  a  resting  spore. 

Ulva,  or  Sea  Lettuce,  is  a  common  form  found  all  over  the 
world,  especially  in  brackish  waters.  In  its  usual  form  it  consists 
of  flat,  thin,  unbranched  fronds  which  are  more  or  less  ovate  or 
orbicular  in  outline  and  frequently  deeply  incised,  sometimes  be- 
coming linear  or  even  ribbon-shaped  (Fig.  n).  The  fronds  con- 
sist of  two  layers  of  cells,  which  are  either  in  close  contact  with 
each  other  or  else  at  maturity  separate  so  as  to  form  a  tubular 
frond.  It  sometimes  occurs  in  large  quantities  in  the  shallow 
water  along  our  coast,  and  is  conspicuously  disagreeable  by  its 
resemblance  in  shape  to  the  swollen  intestines  of  some  animal. 

CEdogonium  is  a  filamentous  alga  occurring  usually  in  simple 
(unbranched  filaments  and  attached  by  a  disk-like  cell  or  hold- 


26  A  TEXT-BOOK  OF  BOTANY. 

fast  (Fig.  II,).  It  occurs  in  meadow  pools  or  ponds,  frequently 
in  streams  attached  to  rocks  near  rapids.  The  cells  are  somewhat 
elongated  and  contain  a  large,  irregular  chromatophore  with 
pyrenoids.  Most  of  the  cells  are  vegetative  cells,  interspersed 
among  which  are  the  cells  producing  the  spores.  Zoospores  are 
produced  singly  in  the  cells  and  are  provided  with  cilia  at  one 
end.  After  swimming  about  for  some  time  they  attach  themselves 
at  this  ciliated  end  to  a  substratum  and  develop  into  filaments. 
Two  other  types  of  cells  are  formed  and  which  give  rise  either 
to  oogonia,  the  female  organ  containing  a  large  egg  cell,  or  to 
antheridia,  the  male  organ  containing  many  sperms.  The  union 
of  a  sperm  with  an  egg  cell  produces  an  oospore  with  a  very  thick 
wall,  capable  of  over-wintering  and  developing  again  when  con- 
ditions are  favorable. 

THE  CHARACE/E,  or  Stoneworts,  is  a  highly  differentiated 
group  that  is  considered  as  a  distinct  class  between  the  Chloro- 
phycese  and  the  Phseophycese.  They  stand  so  entirely  by  them- 
selves that  many  authorities  do  not  consider  them  as  even  Algae. 
They  consist  of  jointed  stems,  from  the  nodes  of  which  whorls  of 
from  4  to  10  leaves  are  developed,  and  these  bear  the  sexual 
organs  (Fig.  13).  In  many  of  the  members  of  this  family  the  cell- 
wall  is  incrusted  with  lime  salts.  Chara  occurs  in  great  masses 
in  the  bottom  of  ponds  and  shallow  lakes.  It  occurs  in  sufficient 
quantity  in  many  places  so  that  the  body  of  water  has  a  distinct 
orange  color,  due  to  the  immense  numbers  of  antheridia.  The 
plant  is  of  such  luxuriant  growth  that  if  single  individuals  are 
kept  in  an  aquarium  or  large  glass  vessel  it  will  greatly  multiply 
during  the  winter  and  persist  for  many  years.  In  ponds  where 
Chara  occurs  large  quantities  of  lime  are  deposited,  so  that  in 
ancient  deposits  now  exposed  to  view  one  often  finds  imbedded 
therein  the  remains  of  the  spore-fruits. 

In  the  long  cells  or  internodes  there  is  a  large  vacuole  and 
a  thin  layer  of  protoplasm  containing  a  central  nucleus  and  a 
large  number  of  oval  or  lens-shaped  chromatophores.  In  some 
forms,  especially  in  Nitella,  the  inner  protoplasmic  layer  shows 
a  streaming  movement.  This  is  very  interesting,  as  a  distinct 
streaming  movement  does  not  occur  in  most  plants  and  is  limited 
to  a  few  water  plants,  the  staminal  hairs  of  Tradescantia,  the  leaf 


PRINCIPAL  GROUPS  OF  PLANTS. 


27 


hairs  of  Cucurbita  and  Urtica  and  the  hyphse  or  Rhizopus,  etc. 
This  streaming  movement  in  plants  like  Characeae,  as  pointed  out 
by  Pfeffer  (Physiology  of  Plants),  has  in  most  cases  a  definite 
purpose.  It  is,  in  any  case,  always  possible  that  the  streaming 
movement  may  be  an  accessory  but  unavoidable  accompaniment 
of  some  other  form  of  vital  activity.  In  Chara  and  Nitella  the 


FIG.  13.  Stonewort  or  Chara.  At  left  showing  the  habit  of  the  plant  with  minute 
reproductive  organs  on  the  leaves.  At  right  enlarged  view  of  reproductive  organs.  A, 
mature  organs  showing  (a)  antheridium,  (S)  oogonium  surmounted  at  the  top  by  a  crown 
of  cells  (c);  b,  stem  of  plant;  /3',  /3",  whorl  of  leaves,  some  of  which  have  been  removed,  as 
at  /3;  B,  a  young  antheridium  (a),  with  young  oogonium  (SK),  together  with  the  adjoining 
cells  of  the  stem;  the  whorl  of  leaves  not  represented. — A,  after  Wille;  B,  after  Sachs. 

streaming  endoplasm  (inner  layer  of  protoplasm)  does  not  cover 
more  than  2  to  3  mm.  per  minute.  The  activity  of  the  streaming 
is  influenced  by  sunlight,  oxygen,  acids,  chloroforn^  etc.  Two 
kinds  of  protoplasmic  streaming  are  recognized  :  ( i )  in  which  the 
movement  is  confined  to  the  layer  enclosing  the  central  vacuole, 
that  is  known  as  "  rotation,"  and  (2)  in  which  the  streaming 
follows  more  or  less  irregular  paths  up  and  down  the  strands  of 
protoplasm,  crossing  the  latter,  which  is  called  "  circulation." 


28  A  TEXT-BOOK  OF  BOTANY. 

Vegetative  reproduction  is  much  like  that  of  the  higher  plants, 
through  the  production  of  root- tubers  or  bulbils,  stem  bulbils,  and 
through  special  branches  arising  at  the  nodes.  The  bulbils  are 
filled  with  starch  and  are  capable  of  over- wintering.  The  sexual 
mode  of  reproduction  is  through  the  activity  of  oogonia  producing 
oospores,  and  antheridia  producing  antherozoids  or  sperms.  These 
are  adjacent  to  each  other  at  the  nodes,  the  oogonium  forming  a 
central  elliptical  cell  which  is  surrounded  by  a  crown  of  cells 
through  which  fertilization  takes  place  (Fig.  13). 

PH^OPHYCEvE. — The  Phseophyceae,  or  Brown  Algae,  are  dis- 
tinguished by  having  brown  chromatophores.  They  are  mostly 
found  in  the  colder  waters  of  the  ocean,  and  are  either  free  or 
attached  to  a  substratum.  They  vary  in  size  from  microscopic 
organisms  to  delicate  filamentous  or  cord-like  forms,  and  may  be- 
come of  enormous  size.  Some  are  called  rock-weeds  and  give  the 
characteristic  color  to  the  rocks  between  low-  and  high-tide  marks. 
Others  are  known  as  "  kelps,"  and  these  grow  near  the  low-water 
mark.  They  vary  in  color  from  an  olive-green  to  a  brown.  The 
chlorophyll  may  be  extracted  by  alcohol,  leaving  the  other  pig- 
ments, phycoxanthin  and  phycophaein.  Many  of  these  Algae  are 
rich  in  iodine,  being  one  of  the  sources  of  this  element.  They  also 
contain  large  quantities  of  sodium,  and  were  used  at  one  time 
in  the  manufacture  of  sodium,  and  have  been  used  to  fertilize  the 
soil  in  parts  of  Europe  as  well  as  in  New  England. 

They  are  more  complex  in  form  than  the  Green  Algae,  and 
are  distinguished  by  having  hold-fasts  which,  while  not  in  the 
nature  of  true  roots,  yet  serve  to  hold  the  plant.  They  may  also 
develop  stems  and  bear  leaf-like  structures  of  many  varied  forms. 
Others  also  develop  swollen  bladders  which  contain  oxygen  and 
which  serve  to  buoy  up  the  plant. 

Fucus,  or  Bladder  Wrack,  is  one  of  the  common  rock-weeds 
(Fig.  14,  B).  It  grows  near  the  surface  of  the  water,  attached 
to  rocks,  and  produces  a  regularly  dichotomously  branching 
thallus.  Some  of  the  forms  in  the  upper  branches  produce  air 
bladders  which  are  spherical  or  slightly  elongated  and  usually  in 
pairs.  The  margins  of  the  branches  are  either  entire  or  somewhat 
serrate.  The  tips  of  older  branches  become  more  or  less  swollen 
and  are  termed  receptacles.  They  are  dotted  over  with  minute 


PRINCIPAL  GROUPS  OF  PLANTS.  29 

cavities,  called  conceptacles,  and  these  contain  the  reproductive 
organs.     These  consist  of  oogonia  and  antheridia,  which  may  be 


FIG.  14.  Some  common  marine  algae.  A.  Laminaria,  showing  portions  of  three  leaf- 
like  thalli  and  hold-fast;  B,  dichotomously  branching  thallus  of  Fucus;  C,  Sargassum,  or 
"gulf  weed,"  showing  a  thallus  resembling  a  leafy  branch,  with  swollen,  berry-like  air 
bladders,  which  act  as  floats;  D,  Dasya,  a  delicate  branching  filamentous  sea-weed,  attached 
to  a  blade  of  eel-grass;  E,  dichotomously  branching  thallus  of  Chondrus,  or  Irish  moss; 
F,  leaf-like  thallus  of  Grinnellia;  G,  densely,  but  delicately  branched  thallus  of  Polysiphonia. 
A,  B,  C  are  Brown  Algae  and  D,  E,  F,  G  are  Red  Algas. 

present  on  the  same  or  on  different  plants.    The  egg  cells  and  the 
sperm  cells  escape  into  the  sea-water,  and  after  their  union  an 


30  A  TEXT-BOOK  OF  BOTANY. 

oospore  results,  which,  upon  finding  a  favorable  resting  place, 
begins  shortly  to  develop  into  new  Fucus  plants.  The  plant 
contains  both  iodine  and  bromine,  chiefly  combined  with  salts  of 
sodium  and  potassium,  and  was  at  one  time  used  in  medicine.  It 
also  contains  a  bitter  principle  and  a  considerable  amount  of 
mucilage. 

ASCOPHYLLUM,  a  rock-weed  closely  related  to  Fucus,  is  dis- 
tinguished from  this  genus  by  the  fact  that  the  branches  are  desti- 
tute of  midribs  and  the  spores  occur  in  groups  of  four  instead  of 
eight.  The  frond  is  thick  and  narrow,  branching  somewhat 
dichotomously,  and  at  intervals  produces  large,  conspicuous  floats, 
which  are  broader  than  the  frond.  The  plants  occur  from  ^  to  2 
metres  in  length.  The  fruit  is  found  in  lateral  branches  in  winter 
and  spring,  and  in  June  the  receptacles  fall  off  and  are  sometimes 
found  in  immense  quantities,  covering  the  bottom  of  tide  pools. 

LAMINARIA  is  one  of  the  common  kelps  or  devil's  aprons  which 
inhabit  principally  the  colder  seas  of  high  latitudes.  They  all 
grow  in  pools  at  low-water  mark,  attached  to  the  rocks  and  in 
deep  water,  and  some  attain  a  very  large  size.  The  species  vary 
greatly  in  outline  and  habit  according  to  the  season  and  place  of 
growth — whether  on  an  exposed  or  sheltered  coast  or  partly  ex- 
posed at  low  tide.  It  consists  of  three  parts  (Fig.  14,  A)  :  a 
long,  leaf-like  expansion  or  blade  supported  by  a  more  or  less 
cylindrical  stalk  or  stipe,  which  in  turn  is  attached  to  the  rocks 
by  a  hold-fast  made  up  of  a  cluster  of  fibrous  outgrowths.  In 
general  the  species  may  be  classed  in  two  groups,  one  in  which 
the  frond  is  ribbon-like  or  long  in  proportion  to  the  breadth  and 
not  split  up  into  segments,  and  the  other  in  which  the  frond  is 
proportionally  broader  and  fan-shaped  and  laciniate.  To  this 
latter  belongs  the  Laminaria  digitata.  There  are  some  25  species, 
distinguished  by  the  arrangement  of  root-fibres  comprising  the 
hold-fast,  the  structure  of  the  stipe,  whether  solid  or  hollow  and 
whether  provided  with  distinct  cavities  containing  mucilage,  the 
shape,  especially  of  the  basal  portion  of  the  lamina,  and  the  char- 
acter of  the  margin  and  the  position  of  the  fruit.  The  growing 
portion  of  the  lamina  is  at  the  base,  as  in  the  leaves  of  the  Spermo- 
phytes.  The  kelps  of  the  Pacific  Ocean  are  among  the  largest 
sea-weeds  known,  the  Giant  Kelp,  Macrocystis,  attaining  a  length 


PRINCIPAL  GROUPS  OF  PLANTS.  31 

of  nearly  a  thousand  feet.  Other  forms  have  large  floats  at  the 
base  of  the  lamina.  Reproduction  is  chiefly  by  zoospores  formed 
in  i -celled  sporangia  which  occur  either  in  dispersed  patches 
or  in  continuous  bands  near  the  centre  of  the  frond. 

SARGASSUM,  or  Gulf  Weed,  grows  attached  to  rocks  by  means 
of  disk-like  hold-fasts  (Fig.  14,  C).  When  it  is  torn  from  the  rocks 
it  is  carried  into  the  open  ocean  by  currents  such  as  the  Gulf 
Stream.  Sargassum  is  most  highly  organized  and  is  represented 
by  a  very  large  number  of  species.  They  are  found  especially  in 
the  warmer  waters  near  Australia,  Japan  and  the  adjacent  coast  of 
Asia,  and  also  in  the  West  Indies  and  at  various  parts  of  the 
Atlantic  Coast  near  the  Gulf  Stream,  some  occurring  as  far  north 
as  Cape  Cod.  The  plants  vary  from  15  cm.  to  nearly  2  metres  in 
length,  and  consist  of  a  stem-like  axis  which  bears  leaf-like 
branches  with  a  distinct  midrib,  berry-like  air  sacs  on  stalks,  and 
reproductive  branches  or  receptacles. 

RHODOPHYCE^E. — This  includes  all  the  Algae  which  are  of  a 
reddish  or  violet  color.  They  contain  chromatophores  in  which, 
the  chlorophyll  is  masked  by  other  pigments,  mostly  red,  and 
known  as  phycoerythrin  or  rhodophyll.  The  red  Algae  are  mostly 
found  in  salt  water,  occasionally  in  fresh  and  running  water. 
They  are  usually  found  growing  upon  other  plants  or  variously 
attached  to  some  substratum.  They  vary  from  microscopic  forms 
or  very  delicate  filamentous  types  to  large  plants.  They  are 
usually  composed  of  a  number  of  cells  or  filaments  which  are 
so  closely  arranged  as  to  resemble  the  tissues  of  higher  plants. 
Many  of  the  cells  are  connected  by  strands  of  protoplasm,  giving 
them  a  rather  characteristic  appearance.  Others  have  an  in- 
crustation of  lime  on  the  wall.  They  are  mostly  found  in  deep 
waters  of  the  Tropics.  Reproduction  is  almost  entirely  by  sexual 
or  asexual  spores. 

CHONDRUS,  or  Carragheen  or  Irish  Moss  (Figs.  15,  16),  is  a 
common  rock-weed  found  at  low-water  mark,  and  in  this  country 
is  common  from  New  York  northward,  being  extensively  col- 
lected at  a  few  points  about  15  to  20  miles  south  of  Boston.  The 
plant  varies  considerably  in  color,  being  more  or  less  green  when 
close  to  the  surface  of  the  water  and  of  a  deep  purplish-red  when 
growing  at  some  depth.  It  varies  from  4  to  15  cm.  in  length,  and 


32  A  TEXT-BOOK  OF  BOTANY. 

is  attached  to  rocks  by  means  of  a  slender  hold- fast.  The  thallus 
is  dichotomously  branching,  somewhat  flattened,  but  may  be  quite 
linear.  The  fronds  show  a  mucilaginous  modification  of  the  cell- 
walls.  In  the  upper  segments  occur  small  differentiated  areas, 


FIG.   15.     Specimen  of  Chondrus  crispus  still  attached  to  the  rock  where  it  was    found 
growing  along  the  Massachusetts  coast. 

sometimes  called  sori,  of  a  more  or  less  elliptical  outline,  which 
on  sectioning  are  found  to  be  in  the  nature  of  sporangia,  contain- 
ing numerous  tetraspores  (Fig.  16).  The  spores  are  discharged 
through  narrow  canals  extending  through  the  more  or  less  com- 
pact outer  layer  of  the  frond.  The  article  found  in  commerce  has 
the  color  removed  by  being  bleached  through  the  action  of  the  sun 


PRINCIPAL  GROUPS  OF  PLANTS! 


33 


and  dews.    It  shows,  however,  all  the  morphological  structure  of 
the  growing  plant. 


FIG.  16.  Chondrus  crispus:  A,  B,  C,  D,  various  forms  of  thallus;  H,  hold-fast;  F, 
sporangia;  T,  transverse  section  of  thallus  showing  epidermis  (E),  sporangium  with  spores 
(F) ;  S,  spores  separated  in  glycerin  preparation  of  thallus  by  pressure  on  the  cover-glass. 
The  spores  occur  in  groups  of  four  (tetraspores)  and  the  tetrad  group  is  about  30^  in  diameter. 

In  a  closely  related  genus,  Gigartina  (Fig.  17),  which  is  found 
in  imported  Chondrus,  the  fruit  bodies  occur  in  numerous  cylindri- 
3 


34  A  TEXT-BOOK  OF  BOTANY. 

cal  outgrowths  developed  on  the  surface  of  the  fronds.  This 
form  is  found  more  abundantly  north  of  Boston  than  south,  but, 
as  Chondrus  is  collected  at  Cohasset,  Scituate,  and  other  towns 
south  of  Boston,  it  is  not  seen  in  commerce  in  this  country. 

RHODYMENIA,  or  Irish  Dulce,  is  one  of  the  commonest  red 
sea-weeds  in  the  North  Atlantic  Ocean,  usually  growing  with  Fucus, 
Laminaria,  and  other  Algae  between  tide  marks  and  extending 
into  deep  water.  The  fronds  are  purplish-red,  flat,  membra* 


FIG.  17.  Gigartina  mamillosa,  a  red  sea-weed  closely  related  to  Chondrus  crispus, 
showing  a  dichotomously  branching  thallus  and  bearing  at  the  upper  part  numerous  cylin- 
drical outgrowths  in  which  the  fruit  bodies  (sporangia)  are  found. — After  Kutzing. 

naceous,  15  to  30  cm.  in  length,  irregularly  cleft,  palmate  or 
dichotomous,  the  margin  often  being  marked  with  numerous 
small  divisions.  The  sporangia  occur  in  scattered  patches  im- 
mersed in  the  cortical  tissues  of  the  frond.  It  is  a  common  article 
of  commerce  and  is  said  to  possess  anthelmintic  properties. 

AGAR-AGAR  is  derived  from  several  of  the  marine  Algae  grow- 
ing along  the  eastern  coast  of  Asia,  notably  species  of  Gracilaria, 
Gelidium,  and  Gloiopeltis.  It  is  a  mucilaginous  substance  which 
is  extracted  from  the  sea-weeds,  and  is  used  extensively  as  a 


PRINCIPAL  GROUPS  OF  PLANTS. 


35 


culture  medium  in  bacteriology  and  in  other  work  where  a  nutrient 
is  desired.  It  occurs  commercially  in  bundles  4  to  6  decimetres  in 
length,  consisting  of  thin,  translucent,  membraneous,  agglutinated 
pieces,  yellowish-white  in  color.  It  is  usually  brittle,  but  becomes 
tough  when  moistened.  It  is  used  in  medicine  in  the  powdered 


FIG.   18.     AracTinoidiscus  Ehrenbergii,  a  characteristic  Diatom  found  in  Agar-agar. — From 
a  photomicrographic  negative  by  J.  J.  Woodward,  Surgeon,  U.  S.  A. 

form.  Under  the  microscope  Agar-agar  frequently  shows  the 
frustules  or  siliceous  cell  walls  of  diatoms,  which  are  disk-shaped 
(Fig.  18).  It  is  insoluble  in  cold  water,  but  dissolves  slowly  in 
hot  water.  Upon  boiling  I  part  in  100  parts  of  water  it  should 
yield  a  stiff  jelly  upon  cooling. 

Diatoms  constitute  a  large  group  of  unicellular  plants,  occur- 


36  A  TEXT-BOOK  OF  BOTANY. 

ring  in  both  fresh  and  salt  waters.  They  form  the  plankton  or 
floating  microscopic  life  found  in  oceans  and  lakes,  which  is  the 
source  of  food  of  small  animal  forms  inhabiting  these  waters. 
The  mud  at  the  mouths  of  many  rivers,  the  sediment  of  ponds, 
ditches,  and  even  rain  troughs  may  contain  great  numbers  of 
these  minute  organisms.  They  have  been  found  in  the  polar 
ice,  and  have  been  detected  in  the  dust  evolved  from  volcanoes. 
One  of  the  distinguishing  characters  of  the  group  is  that  the  cell 
wall  is  incrusted  with  silica.  For  this  reason  they  are  practically 
indestructible  and  form  marls  and  strata  in  the  earth.  They  occur 
either  singly  or  grouped  in  bands  or  chains.  They  are  very 
variable  in  shape,  being  boat-shaped,  ellipsoidal,  spherical,  or 
peculiarly  curved  in  some  forms.  They  are  either  free  or  attached 
to  a  substratum,  as  stones,  water  plants,  etc.,  those  which  are 
free  having  an  active  movement  (Fig.  19). 

The  cell  wall  of  Diatoms  practically  consists  of  two  halves,  one 
fitting  over  the  other  like  the  lid  of  a  box.  These  are  known 
as  "  valves  "  or  "  theca."  The  manner  in  which  the  two  valves 
are  joined  results  in  the  formation  of  a  "  girdle  "  or  "  pleura." 
The  girdle  is  provided  with  a  series  of  pores  conecting  with 
canals  at  either  end  and  in  the  middle,  through  which  food  from 
without  is  supplied  to  the  protoplast.  The  valves  are  very  often 
beautifully  marked  by  a  series  of  parallel  cross  lines,  dots,  cir- 
cles, or  polygons,  which  are  characteristic  of  the  different  groups. 
Some  forms  are  used  in  testing  the  definition  of  objectives,  as 
Pleurosigma  angulatum,  in  which  the  lines  are  one-half  micron 
(0.0005  mm.)  wide  (Fig.  19,  A). 

In  the  Diatoms  the  protoplasm  lies  as  a  thin  layer  close  to  the 
wall  surrounding  a  large  central  vacuole.  The  nucleus  is  sur- 
rounded by  a  relatively  dense  mass  of  cytoplasm,  and  occurs  in 
definite  positions  according  to  the  species.  The  chromatophores 
frequently  occur  in  plates  which  are  typical  for  certain  species. 
They  are  sometimes  greenish-yellow,  the  color  being  generally 
masked  by  the  presence  of  a  brown  substance  known  as  diatomin. 
They  frequently  contain  pyrenoids,  which  are  sometimes  asso- 
ciated with  granules  of  starch. 

Reproduction  takes  place  by  simple  division  or  fission,  the  two 
valves  separating  and  a  new  valve  forming  on  each  half  to  replace 


PRINCIPAL  GROUPS  OF  PLANTS. 


37 


the  old  one.  In  each  case  the  valve  formed  fits  into  the  old  one, 
and  hence  in  the  case  of  the  smaller  valve  the  new  cell  or  plant 
becomes  smaller  than  the  parent  plant,  the  walls  not  being  able 
to  expand  on  account  of  the  siliceous  composition.  In  this  way 
the  cells  of  one  series  gradually  becomes  smaller  and  smaller  until 
a  certain  minimum  is  reached,  when  the  plant  rejuvenates  itself 


FIG.  19.  Diatoms:  A,  Pleurosigma  attenuatum  as  seen  from  above;  B,  Pleurosigma 
baUicum  as  seen  from  the  girdle  side;  C,  D,  E,  Fragilaria  virescens  showing  colonies  attached 
to  an  alga  in  C,  a  view  of  a  single  diatom  from  above  at  D,  and  a  chain  of  diatoms  viewed 
frorr  the  girdle  side  at  E;  F,  G,  two  views  of  Navicula  viridis;  H,  I,  the  formation  of  auxo- 
spores  in  Navicula  firma,  H  showing  the  exit  of  the  protoplasts  and  the  throwing  off  of  the 
original  valves. — A,  B,  D,  after  Van  Heurck;  C,  E,  after  W.  Smith;  F-I,  after  Pfitzer. 

by  the  production  of  spores  (auxospores).  These  are  formed  in 
two  ways:  In  one  case  the  valves  separate  from  each  other,  the 
protoplast  escapes,  grows  larger  and  develops  a  new  wall ;  in  the 
other  case,  of  which  there  are  several  types,  two  individuals  come 
together,  and  envelop  themselves  in  a  mucilaginous  covering. 
They  then  throw  off  their  siliceous  walls  and  the  protoplasts 
unite  to  form  a  zygospore,  which  grows  until  it  is  three  times  the 


38  A  TEXT-BOOK  OF  BOTANY. 

original  size,  after  which  it  develops  a  new  wall,  the  larger  valve 
forming  first  (Fig.  19,  H,  I). 

DIATOMACEOUS  EARTH,  also  known  commercially  as  "  In- 
fusorial Earth,"  or  "  Kieselguhr "  (meaning  siliceous  marl), 
occurs  in  extensive  deposits,  some  of  these,  as  the  stratum  at 
Richmond,  Va.,  extending  to  a  depth  of  18  feet.  These  deposits 
consist  of  the  siliceous  walls  of  the  Diatoms,  which,  owing  to  their 
composition,  are  practically  indestructible,  and  are  accumulated 
in  those  localities  which  have  favored  the  growth  of  the  organ- 
ism. The  natural  deposit  is  mined  and  usually  calcined  to  de- 
stroy the  organic  matter,  after  which  it  is  washed  and  dried. 
The  article  used  in  pharmacy  is  further  purified  by  boiling  with 
diluted  hydrochloric  acid,  washing,  and  calcining.  This  purified 
product  is  known  as  Terra  Silicea  Purificata,  and  occurs  in  the 
form  of  an  almost  whitish,  or  light  grayish,  or  light  brown  powder. 
It  is  odorless,  insoluble  in  water  and  in  mineral  acids  or  dilute 
solutions  of  the  alkalies.  Under  the  microscope  mounts  made  in 
water  or  solutions  of  hydrated  chloral  show  the  frustules  or 
siliceous  walls  of  the  Diatoms.  In  the  better  grades  of  Diatoma- 
ceous  Earth  the  entire  skeleton  with  the  characteristic  markings  is 
present.  Material  coming  from  various  localities  shows  a  differ- 
ence in  genera  of  Diatoms.  The  exact  naming  of  the  species 
requires  the  assistance  of  specialists.  In  order  to  avoid  confusion 
it  is  necessary  to  bear  in  mind  that  there  are  two  and  sometimes 
even  three  views  which  may  be  obtained  of  the  same  Diatom. 

Diatomaceous  Earth  consists  of  about  85  per  cent,  of  SiO2, 
10  per  cent,  of  water,  and  5  per  cent,  of  clay,  iron  oxide,  magnesia, 
lime,  and  organic  material.  Owing  to  the  fact  that  Diatomaceous 
Earth  is  made  up  of  the  hollow  shells  of  Diatoms,  it  has  the 
property  of  absorbing  by  capillarity  gases  and  liquids.  For  this 
reason  it  is  used  in  the  preparation  of  dynamite ;  the  highly  ex- 
plosive nitroglycerin  being  absorbed  by  the  diatomaceous  shells, 
render-ing  the  product  capable  of  being  handled.  When  calcined, 
it  will  absorb  its  own  weight  of  water.  It  is  used  in  pharmacy  for 
filtering  and  as  a  diluent  for  powdered  extracts,  etc.  Among  the 
technical  uses  may  be  mentioned :  polishing  of  metals  and  woods, 
insulating  steam  pipes  and  electrical  insulators,  packing  of  caustic 
and  inflammable  liquids,  and  the  manufacture  of  glass,  paper,  and 


PRINCIPAL  GROUPS  OF  PLANTS. 


39 


soap.  It  is  also  used  to  some  extent  in  dermatology.  In  India  it 
has  been  used  as  a  rubefacient.  In  Sweden,  and  among  the 
Chinese  and  Laplanders,  Diatomaceous  Earth  has  been  used  as  an 


FIG.  20.  The  Algae  are  put  to  various  uses  by  the  people  who  collect  them.  The 
illustration  is  taken  from  an  ornament  purchased  at  the  Louisiana  Purchase  Exposition 
and  was  made  by  the  Filipinos  from  various  kelps  having  large,  bladder-like  floats. 

edible  earth  under  the  name  of  "  mountain  meal  "  or  "  bread- 
stone.''  Humboldt  also  calls  attention  to  the  fact  (Aspects  of 
Nature)  that  the  practice  of  eating  earth  is  diffused  throughout 
the  torrid  zone,  among  indolent  races  inhabiting  the  finest  and 


40  A  TEXT-BOOK  OF  BOTANY. 

most  fertile  parts  of  the  globe.  It  is  a  saying  even  among  the 
most  distant  of  the  different  tribes  living  on  the  Orinoco,  when 
speaking  of  anything  very  unclean,  that  it  is  "  so  dirty  that  the 
Otomacs  eat  it." 

ECONOMIC  USES  OF  ALGJE. — Many  of  the  Algae  are  of  use  as 
food,  of  which  the  following  may  be  mentioned :  Vaucheria  fasti- 
giata,  Griffrthsia  coralina,  Ceramium  Loureirii,  Chondrus  crispus, 
Gigartina  mamillosa,  Gelidium  cartilagineum,  Gelidium  crinale 
(yielding  agar-agar),  Rhodymenia  palmata  (yielding  dulse),  and 
several  species  of  Gracilaria  (which  also  yield  agar-agar). 

Some  of  the  sea-weeds  are  used  in  the  production  of  iodine, 
as  Durvillcca  utilis,  Ascophyllum  nodosum,  Fucus  vesiculosus 
(bladder-wrack),  Sargassum  linifolium,  Laminaria  saccharina, 
Laminaria  digitata,  Alaria  esculenta,  Rhodymenia  palmata,  Phyl- 
lophora  membranifolia,  Macrocystis  pyrifera,  and  Fastigiaria 
furcellata. 

A  number  of  the  Algae  are  also  used  in  medicine,  particularly 
for  phthisis,  as  Fucus  cartilagineus}  Stilophora  rhizodes  and 
Dictyopteris  polypodioides.  Alaria  esculenta  and  Laminaria  digi- 
tata are  used  in  the  making  of  bougies  and  tents  used  in  surgery. 
Owing  to  the  toughness  of  some  of  the  Algae  on  drying,  the 
material  is  used  in  the  manufacture  of  various  articles,  as  handles 
for  tools  from  the  thick  stem  of  Lessonia  jucescens,  fishing  lines 
from  Chordaria  flagelliformis  (Fig.  20),  etc. 

FUNGI. 

The  Fungi  form  a  large  group  of  plants  which  do  not  produce 
chloroplasts  or  any  bodies  having  a  similar  function.  They  have 
not  the  power  of  carbon  dioxide  assimilation, — that  is,  unlike  the 
Algse,  they  are  unable  to  manufacture  food  materials,  such  as 
carbohydrates  (starches,  sugars,  etc.),  from  carbon  dioxide  and 
water.  Hence  they  are  dependent  upon  previously  formed  food 
products,  and  may  derive  their  food  from  living  plants  or  ani- 
mals, when  they  are  known  as  PARASITES,  or  from  decaying  animal 
or  vegetable  matter,  when  they  are  known  as  SAPROPHYTES.  The 
living  plant  or  animal  atacked  by  a  fungus  is  known  as  the  host. 

Fungi  are  especially  characterized  by  the  habit  of  arising 
from  spores  and  of  producing  thread-like  cells  the  growing  point 


PRINCIPAL  GROUPS  OF  PLANTS.  41 

of  which  is  at  the  apex.  These  threads  are  known  as  HYPH;E 
(singular  hypha).  They  branch  and  become  interwoven,  forming 
a  mass  or  mat  known  as  the  MYCELIUM  (Fig.  23).  The  myce- 
lium constitutes  the  plant  body  proper,  and  absorbs  the  food 
material  from  the  substratum,  which  it  ramifies,  often  causing 
decay.  The  mycelium  is  frequently  not  visible,  and  the  presence 
of  the  fungus  is  not  recognized  until  the  so-called  fruit  bodies  are 
developed,  as  sometimes  seen  in  the  case  of  moldy  oranges, 
mildewed  linen,  and  as  illustrated  by  the  common  mushroom. 
The  mycelium  has  a  cellulose  wall  which  in  some  cases  is  modi- 
fied to  chitin,  a  nitrogenous  substance  related  to  animal  cellulose 
and  found  in  crabs  and  other  lower  animals.  The  protoplasm 
either  occurs  in  a  more  or  less  delicate  form  lining  the  hyphse  and' 
enclosing  large  vacuoles,  or  is  comparatively  dense  enclosing 
numerous  small  vacuoles.  Many  Fungi  contain  color  substances 
which  are  dissolved  in  the  cell-sap  and  are  of  a  quite  brilliant  hue. 
One  of  the  most  interesting  classes  of  substances  produced  by 
Fungi  is  that  of  the  ferments,  including  the  oxidizing  ferment 
allied  to  laccase.  They  contain  also  amido-substances  related  to 
lecithin ;  fats ;  carbohydrates,  as  trehalose  and  mannitol ;  organic 
acids,  as  oxalic,  tartaric,  malic,  etc. ;  and  calcium  oxalate  may 
be  present  in  some  cases. 

Reproduction  in  the  Fungi  is  chiefly  by  means  of  asexual 
spores,  which  arise  in  two  ways.  In  the  one  case  they  are  devel- 
oped in  a  special  cell  or  sporangium  at  the  end  of  a  mycelial  thread 
and  are  known  as  ENDOSPORES.  In  the  other  case  they  arise  on 
special  hyphse,  or  directly  from  the  mycelium,  and  are  known  as 
EXOSPORES  or  conidia.  There  are  also  several  modifications  of 
these  two  types  .of  spores,  which  may  be  referred  to  later. 

Groups  of  Fungi. — There  are  four  principal  groups  of  Fungi : 

1.  Phycomycetes. 

2.  Basidiomycetes. 

3.  Ascomycetes. 

4.  Fungi  Imperfecti. 

The  Phycomycetes,  or  Algal-like  Fungi,  are  so  called  because 
they  show  a  certain  relation  to  the  Algae. 

The  Ascomycetes  are  distinguished  by  having  a  sporangium  of 


42  A  TEXT-BOOK  OF  BOTANY. 

a  definite  shape  and  size,  which  is  called  an  ASCUS,  and  which 
contains  a  definite  number  of  spores,  which  is  two  or  some  multi- 
ple thereof. 

The  Basidiomycetes  are  the  most  highly  developed  Fungi, 
producing  large  fruit  bodies,  such  as  are  seen  in  mushrooms,  toad- 
stools, and  puffballs.  They  are  characterized  by  producing  spores 
(basidiospores)  on  special  hyphae.  The  spores  are  usually  four 
in  number,  and  the  spore-producing  organ  is  known  as  a  BASIDIUM. 

The  Fungi  Imperfecti  constitute  a  group  of  Fungi  which, 
while  having  certain  natural  relationships  with  the  other  types 
already  considered,  yet  do  this  so  imperfectly  that  they  are  brought 
in  a  class  by  themselves.  The  complete  life-cycle  is  not  in  all  cases 
known,  and  future  studies  will  probably  distribute  them  among 
the  other  principal  groups. 

PHYCOMYCETES :  ALGA-FUNGI— The  plant  body  of 
the  Phycomycetes  consists  of  a  mycelium  which  is  unsegmented, 
more  or  less  thread-like  and  sometimes  considerably  branched. 
Reproduction  takes  place  by  means  of  several  kinds  of  spores,  and 
by  reason  of  the  production  of  two  kinds  of  sexual  spores  they  are 
subdivided  into  two  important  groups.  These  are  ( I )  the  Oomy- 
cetes,  which  produce  oospores,  and  (2)  Zygomycetes,  which 
produce  zygospores. 

Saprolegnia. — Probably  one  of  the  best  representatives  of 
the  Oomycetes  is  the  group  of  water  molds  known  as  Saproleg- 
nia, which  are  aquatic  in  their  habits  and  are  both  parasitic  and 
saprophytic,  occurring  on  living  fish,  insects,  crayfish  and  decay- 
ing plants  and  animals  as  well.  The  plant  body  consists  of  a 
mycelium  which  may  be  simple  or  branched,  sometimes  forming 
a  dense  mass  (Fig.  21,  A).  Like  the  alga  Vaucheria,  it  produces 
both  swarm  spores  (zoospores)  and  oospores.  The  swarm  spores 
(Fig.  21,  B,  C)  are  produced  in  sporangia  formed  by  the  pro- 
duction of  a  partition  wall  at  the  end  of  a  hypha.  The  sporangia 
are  either  cylindrical  or  spherical,  and  contain  numerous  zoospores 
which  have  two  cilia  at  one  end.  These  spores  are  peculiar  in 
that  after  their  escape  from  the  sporangium  they  swim  about, 
then  come  to  rest  and  take  on  a  wall,  after  which  resting  period 
they  develop  two  cilia  on  the  side,  again  move  about,  and  germi- 
nate when  they  find  a  suitable  host. 


PRINCIPAL  GROUPS  OF  PLANTS. 


43 


The  oogonia  and  antheridia  (Fig.  21,  D-F)  are  also  formed 
at  the  ends  of  hyphse.  The  oogonia  are  usually  spherical  and  the 
wall  contains  a  number  of  small  pores.  The  contents,  which  are 
at  first  more  or  less  uniform,  later  develop  egg-cells,  of  which 
there  may  be  as  many  as  fifty  in  a  single  oogonium.  The  anthe- 
ridium  is  more  or  less  cylindrical  and  contains  a  somewhat  uni- 


F 


FIG.  21.  Species  of  Saprolegnia:  A,  mycelium  growing  out  from  and  surrounding 
a  dead  house-fly  in  a  water  culture;  B,  C,  sporangia  with  biciliate  swarm  spores;  D,  a  num- 
ber of  oogonia  containing  oospheres;  E,  F,  oogonia  and  antheridia,  in  F  the  tube  of  the 
antheridium  having  penetrated  the  oogonium.— A-C,  after  Thuret;  D-F,  after  De  Bary. 

form  mass  of  protoplasm.  The  antheridium  bends  toward  the 
oogonium  and  comes  in  contact  with  it,  but  apparently  does  not 
in  all  cases  penetrate  it.  Nevertheless  the  egg-cells  develop  walls 
and  become  resting  oospores. 

In  Peronospora,  one  of  the  Oomycetes,  the  antheridium 
(Fig.  22,  n)  develops  a  tube  which  pierces  the  wall  of  the 


44 


A  TEXT-BOOK  OF  BOTANY. 


oogonium  (Fig.  22,  o)  ;  the  contents  unite  with  the  egg-cell, 
after  which  a  heavy  membrane  develops,  forming  an  oospore, 
which  germinates  when  it  finds  a  suitable  host.  The  plants 
belonging  to  Peronospora  as  well  as  related  genera  are  destruc- 


FIG.  22.  A,  Cyslopus  candidus;  B,  Peronospora  calotheca.  Mycelia  (m)  with  haustoria 
penetrating  cells  (z)  of  hosts.  C,  Oospore  formation  in  Peronospora:  o,  oogonium;  n,  anthe- 
ridium.  At  the  left  the  antheridium  is  in  contact  with  oogonium;  the  next  stage  shows  the 
antheridium  penetrating  oogonium  and  discharging  its  contents;  at  the  right  the  resulting 
oospore  is  shown. — After  De  Bary. 

tive  to  many  cultivated  plants,  constituting  mildews  or  blights, 
as  those  occurring  on  the  leaves  of  hyoscyamus,  tobacco,  anthe- 
mis,  matricaria,  aconite,  grape  vine,  lima  bean,  potato,  etc.  The 
group  has  received  the  name  "downy  mildews  "  because  of  the 


PRINCIPAL  GROUPS  OF  PLANTS. 


45 


fact  that  the  conidiophores   rise  to  the   surface  of  the  leaves 
where  the  spores  are  discharged,  forming  powdery  patches. 

Black   Mold. — A   common   example   of   the   Zygomycetes   is 
furnished  by  the  "  black  mold,"  Mucor  Mucedo.     The  mycelium 


FIG.  23.  B,  richly  branching  mycelium  (m)  of  the  mold  Phycomyccs  nitens  showing 
upright  hyphae  bearing  sporangia  (g).  A,  C,  D,  the  common  black  mold  Mucor  Mucedo. 
A,  sporangium  with  columella;  C,  germination  of  zygospore  (z),  with  formation  of  hypha 
(k),  and  sporangium  (g);  D,  earliest  stages  in  the  development  of  a  zygospore,  the  hyphal 
branches  (b)  showing  adjoining  ends  (a)  cut  off  by  cross  walls. — After  Sachs. 

of  this  plant  is  ccenocytic,  thread-like,  very  much  branched,  arid 
profusely  developed,  much  like  that  of  Phycomyces  nitens  (Fig. 
23,  B).  This  mold  is  widely  distributed,  causing  trouble  in  the 
spoiling  of  many  sugar-  and  starch-containing  substances  in  the 
household,  including  preserves,  syrups,  fruits,  etc.  In  fact,  a 


46  A  TEXT-BOOK  OF  BOTANY. 

number  of  species  of  Mucor  have  the  power  of  inducing  alcoholic 
fermentation  in  glucose-containing  solutions.  They  are  also 
commonly  found  in  many  aqueous  solutions  of  inorganic  chemicals 
as  well  as  organic  substances.  Asexual  spores  are  formed  at  the 
ends  of  hyphae  which  rise  into  the  air.  The  sporangia  are  spherical 
and  are  cut  off  from  the  hyphae  by  means  of  a  transverse  wall 
which  projects  upward  into  the  sporangium  and  which  is  techni- 
cally known  as  the  columella  (Fig.  23,  A).  The  contents  by 


FIG.  24.  Peziza  confluens  showing  stages  in  the  development  of  ascospores.  In  the 
youngest  asci  (m,  r)  there  is  only  one  nucleus;  this  divides  into  two  (s^;  the  division  is 
repeated,  so  that  there  are  4  nuclei  in  (t)  and  8  in  (n).  These  surround  themselves  with 
protoplasm  and  a  cell-wall  (v,  w),  but  the  protoplasm  of  the  mother  cell  or  ascus  is  not  entirely 
used  up. — After  De  Bary. 

simultaneous  division  form  numerous  I -celled  spores,  which  are 
discharged  by  the  bursting  of  the  sporangium  wall  and  distributed 
by  air-currents  or  the  wind.  As  the  name  of  the  group  to  which 
this  plant  belongs  indicates,  it  also  produces  zygospores  (Fig. 
23,  £>).  These  are  formed  by  hyphal  branches  which  ascend 
from  the  substratum.  The  ends  of  two  branches  come  together, 
a  transverse  wall  is  formed  in  each  branch,  the  walls  in  contact 
are  absorbed,  the  contents  unite,  and  a  spore  is  formed  with 


PRINCIPAL  GROUPS  OF  PLANTS. 


47 


three  membranes,  two  belonging  to  the  spore  proper  and  the  third 
being  formed  by  the  united  hyphae.  As  would  be  expected,  these 
spores  are  quite  resistant,  being  able  to  withstand  unfavorable 
conditions,  and  germinate  (Fig.  23,  C)  only  after  a  period  of  rest. 
ASCOMYCETES. — The  Ascomycetes  are  distinguished  for 
the  most  part,  like  the  other  higher  Fungi,  in  having  a  septate 
mycelium,  i.e.,  one  cellular  in  structure,  and  in  producing  asci 


FIG.  25.  Species  of  Saccharomyces  (Yeasts).  A,  5.  cerevisice  or  beer  yeast;  B,  S. 
Pastorianus;  C,  S.  glomeratus;  D,  S.  Piculatus:  a,  vegetative  cells  reproducing  by  budding; 
b,  formation  of  ascospores. — After  Reesz. 

(sacs),  which  latter  are  formed  at  the  ends  of  the  branches  of 
the  mycelia.  Two  main  sub-groups  are  recognized,  the  one 
producing  an  indefinite  number  of  spores  in  asci  which  are  not 
well  developed,  and  known  as  the  HEM i ASCI  ;  the  other  producing 
la  definite  number  of  spores,  which  number  is  characteristic  for 
each  species,  in  a  well-developed  ascus,  and  known  as  the  EUASCI. 
In  the  latter  group  the  spores  arise  by  successive  divisions  of  the 
primary  nucleus  into  two,  as  shown  in  Peziza  confluens  (Fig.  24). 
Yeasts. — The  simplest  of  the  Ascomycetes  is  the  sub-group 
known  as  the  Saccharomyces,  or  Yeasts.  The  Yeasts  do  not 
produce  a  mycelium,  but  the  plant  body  consists  of  a  single  cell, 
or  a  chain  of  cells,  and  multiplies  by  a  peculiar  process  known 
as  "yeast  budding"  (Fig.  25,  a).  From  either  end  of  the  cell 
a  wart-like  process  develops,  which  enlarges  until  about  the  size 


48  A  TEXT-BOOK  OF  BOTANY. 

of  the  original  cell,  from  which  it  is  then  separated  by  the  forma- 
tion of  a  transverse  wall.  The  cells  are  spherical,  ellipsoidal,  or 
egg-shaped,  and  in  some  cases  somewhat  elongated  and  hypha- 
like.  In  the  protoplasm  are  one  or  more  large  vacuoles.  In 
certain  of  the  cells,  which  may  be  considered  to  be  asci,  two  to 
eight  spherical  or  ellipsoidal  spores  are  produced  (Fig.  26). 
There  are  a  number  of  different  species  of  Yeasts,  some  of  which 


FIG.  26.     Formation  of  ascospores  in  a  number  of  different  species  of  Yeasts.      I,  Sac- 
charomyces  cerevisice;  2,  S.  Pastorianus;  3,  5.  intermedius;  4,  5.  validus. — After  Hansen. 

are  cultivated ;  and  these  latter  are  of  great  economic  importance 
on  account  of  their  property  of  inducing  alcoholic  fermentation. 
They  are  also  of  use  in  the  making  of  bread,  changing  the  carbo- 
hydrates in  part  into  carbon  dioxide  and  alcohol,  both  of  which 
are  driven  off  in  the  baking. 

The  property  of  yeast  causing  the  fermentation  of  a  solution 


PRINCIPAL  GROUPS  OF  PLANTS.  49 

of  sugar  whereby  alcohol  is  formed,  was  for  a  long  time  supposed 
to  be  due  to  the  presence  of  the  living  yeast  cell  or  to  the  action 
of  living  yeast  protoplasm,  and  hence  fermentation  brought  about 
by  living  organisms  was  distinguished  from  those  fermentative 
processes  where  distinct  principles  such  as  diastase  were  involved  ; 
the  former  being  known  as  "  organized  "  ferments,  while  the 
latter  were  referred  to  as  "  unorganized  "  ferments.  Biiclmer 
obtained  from  freshly  expressed  yeast  a  nitrogenous  substance 
capable  of  changing  solutions  of  cane  sugar  or  glucose  into  alcohol 
and  carbon  dioxide.  This  principle  he  termed  zymase,  and  it 
has  all  of  the  properties  of  an  enzyme  or  ferment  and  behaves 
exactly  as  the  living  yeast  cell  in  a  sugar  solution.  In  the  living 
yeast  plant  zymase  is  continually  being  formed  and  decomposes  the 
sugar  which  has  diffused  into  the  cell. 

Yeasts  are  used  in  the  treatment  of  certain  skin  diseases,  their 
action  being  attributed  to  a  fatty  substance,  ceridine.  Other 
principles  found  in  yeasts  as  well  as  extracts  are  used  in  the 
treatment  of  cancer. 

Under  the  name  of  Xerase  a  mixture  is  marketed  consisting 
of  150  parts  of  dried  beer  yeast,  20  parts  of  dextrose,  125  parts 
of  white  clay  or  aluminum  silicate,  and  3  parts  of  a  mixture  of 
nutritive  salts.  It  is  used  in  the  treatment  of  putrid  wounds, 
ulcers,  etc. 

The  ginger  beer  plant,  which  is  used  in  England  for  making  a 
beverage  known  as  ginger  beer,  consists  of  a  yeast  (Saccharo- 
myces  pyriformis)  and  a  bacteria  (Bacterium  vermiforme) . 
These  two  organisms  live  in  a  somewhat  symbiotic  relationship,  the 
yeast  changing  the  sugar  into  alcohol  and  the  bacteria  developing 
lactic  acid  (see  Technical  Mycology,  by  Lafar). 

Green  and  Yellow  Mildews. — To  the  Ascomycetes  also  be- 
long the  green  and  yellow  Mildews,  Penicillium  and  Aspergillus, 
so  common  in  the  household,  the  dairy,  and  the  granary.  These 
plants  produce  profusely  branching  mycelia  which  form  patches 
upon  or  just  under  the  surface  of  the  materials  upon  which  they 
grow.  These  areas  become  soft  and  spongy  and  are  always  white 
at  first.  After  a  time  hyphal  branches,  which  are  more  or  less 
flask-shaped,  rise  above  the  substratum,  and  by  a  process  of 
division  at  the  end  of  the  branch,  or  conidiophore,  a  spore  called 
4 


5o  A  TEXT-BOOK  OF  BOTANY. 

a  conidiospore  is  formed  (Fig.  27,  A;  Fig.  28,  A).  The  process 
of  division  at  the  end  of  the  conidiophore  continues  from  below 
until  a  chain  of  conidiospores  is  formed.  The  conidiophore  fre- 
quently branches,  so  that  a  fan-like  series  or  group  of  conidia  or 


FIG.  27.  Penicillium,  a  green  mildew.  A,  richly  branching  mycelium  with  conidio- 
phores;  B,  enlarged  view  of  conidiophore  showing  chains  of  conidia;  G,  D,  E,  F,  successive 
stages  in  the  development  of  a  perithecium;  G,  H,  J,  development  of  asci;  K,  groups  of 
asci  containing  from  4  to  8  ascospores;  L,  ascospores  seen  from  the  side  and  showing  char- 
acteristic markings. — After  Brefeld. 

conidiospores  is  produced  (Fig.  27,  B;  Fig.  28,  A).  The  conidia 
are  usually  some  shade  of  green,  but  finally  they  may  become  more 
or  less  brown.  They  are  thin-walled,  quite  small,  and  so  light 
that  they  float  freely  in  the  air.  If  a  colony  is  inhaled  it  gives 


PRINCIPAL  GROUPS  OF  PLANTS.  51 

the  sensation  commonly  called  the  "  smell  of  mold."  They  are 
capable  of  germinating  on  almost  everything,  as  old  shoes,  old 
paper,  as  well  as  on  bread  and  other  articles  of  the  household,  and 
are  commonly  found  on  "  moldy  drugs,"  and  may  occur  in  pharma- 
ceutical preparations,  as  syrups  and  infusions,  and  even  in  solu- 
tions of  inorganic  as  well  as  organic  chemicals. 

Aspergillus  (Fig.  28)  is  distinguished  from  Penicillium  (Fig. 


FIG.  28.  Aspergillus.  a  yellow  mildew.  A,  conidiophore  with  enlarged,  more  or  less 
spherical  end,  from  which  the  fan-like  series  of  chains  of  conidia  arise;  B-E,  successive 
stages  in  the  development  of  perithecium;  F,  section  through  a  nearly  ripe  perithecium; 
G,  groups  of  young  asci;  H,  a  ripe  ascus  with  8  spores. — A,  after  Kny;  B-H,  after  De  Bary. 

27)  by  the  fact  that  the  upper  end  of  the  hyphal  branch  or  conidio- 
phore is  somewhat  enlarged  and  more  or  less  spherical. 

In  addition  to  the  conidiospores  these  Fungi  sometimes  produce 
in  the  fall  of  the  year,  particularly  when  grown  upon  bread,  asci 
fruits  (Fig.  27,  C-F;  Fig.  28,  B-E}.  In  this  case  two  fertile  ini- 
tial hyphae  wind  themselves  around  each  other,  after  which  they 
become  surrounded  with  sterile  branches  which  form  a  kind  of 


52  A  TEXT-BOOK  OF  BOTANY. 

loose  tissue,  more  or  less  cellular  in  structure,  that  finally  develops 
into  a  yellowish  leathery  wall.  This  body,  which  may  be  regarded 
as  a  closed  ascocarp,  is  known  as  a  perithecium  (Fig.  27,  F;  Fig. 
28,  F).  As  a  result  of  the  conjugation  of  the  fertile  cells,  asci 
(Fig.  27,  G,  H,  J ;  Fig.  28,  G,  H)  develop  within  the  perithecium, 
which  are  more  or  less  spherical  or  ellipsoidal  and  contain  from 
four  to  eight  spores  (ascospores)  (Fig.  27,  K;  Fig.  28,  H). 
After  maturity  the  cellular  tissue  around  the  asci  dries  up  and  dis- 
integrates, the  walls  of  the  asci  dissolve,  and  the  ascospores  are 
liberated  from  the  perithecium  by  slight  pressure.  The  spores 
lie  over  winter  and  then  germinate,  producing  a  mycelium  from 
which  conidia  first  develop  and  afterwards  the  perithecia,  thus 
repeating  the  life  history  of  the  plant. 

Ergot. — Another  Ascomycete  of  special  interest  is  the  fungus 
known  as  Ergot  (Clamceps  purpurea).  The  spores  of  this 
fungus  germinate  on  the  flowers  of  certain  grasses.  The  myce- 
lium penetrates  the  walls  of  the  ovary,  absorbing  the  nutriment. 
After  a  time  the  mycelium  develops  on  the  surface,  and  from 
this  short  conidiophores  arise  bearing  small  ovoid  conidia  (con- 
idiospores)  (Fig.  29,  A).  The  mycelium  secretes  a  sweet  fluid, 
the  so-called  honey  dew  which  attracts  insects,  and  thus  the 
conidia  are  carried  to  other  plants.  As  the  conidia  are  capable  of 
immediate  germination  the  so-called  "  ergot  disease "  rapidly 
spreads  during  the  flowering  season  of  the  host  plants.  After  the 
formation  of  conidia  ceases,  the  mycelium  forms  a  dense  mass 
which  is  surrounded  by  a  dark  layer,  and  this,  if  developed  upon 
rye,  constitutes  the  ergot  grains  (Fig.  29,  B)  used  in  medicine, 
these  grains  being  a  number  of  times  larger  than  the  rye  grains 
which  they  replace.  The  mycelial  tissues  connected  with  the  host 
plant  die,  and  the  ergot  drops  to  the  ground.  At  this  stage  the 
ergot  mass  is  more  or  less  cellular  in  structure  and  is  known  as  the 
SCLEROTIUM.  It  is  quite  resistant  and  usually  remains  dormant 
until  the  following  spring  when  the  grasses  are  in  flower  again. 
The  sclerotium  then  shows  signs  of  renewed  activity  by  the  de- 
velopment of  small,  reddish,  spherical  bodies  with  a  fair-sized 
stalk  (Fig.  29,  C).  Within  the  periphery  of  these  spherical  heads 
are  produced  flask-shaped  perithecia  or  ascocarps  (Fig.  29,  D) 


PRINCIPAL  GROUPS  OF  PLANTS. 


53 


containing  numerous  cylindrical  asci  (Fig.  29,  E),  each  of  which 
contains  eight  spores  (Fig.  29,  F)  ;  the  latter  are  i -celled,  hya- 
line, and  thread-like  (Fig.  29,  H ).  These  spores  are  carried  by 


J)  ' 


FIG.  29.  Claviceps  pur  pur  ea.  A,  mycelium  developing  conidia;  B,  an  ear  of  rye 
with  a  number  of  lipe  sclerotia  replacing  grains  of  rye,  and  known  as  ergot;  C,  sclerotium 
developing  spherical  fruit  bodies;  D,  fruit  body  in  longitudinal  section  showing  numerous 
flask-shaped  perithecia  at  the  periphery;  E,  enlarged  perithecium  with  numerous  cylin- 
drical asci;  F,  closed  ascus  with  8  ascospores;  G,  discharge  of  ascospores;  H,  single  thread- 
like ascospore. — A,  after  Brefeld;  B,  after  Schenck;  C-H,  after  Tulasne. 

the  wind  to  the  flowers  of  certain  of  the  grasses,  as  already  stated, 
and  the  life  history  or  cycle  of  growth  begins  again. 


54 


A  TEXT-BOOK  OF  BOTANY. 


Chestnut  Bark  Disease  is  caused  by  a  fungus  parasite  known 
as  Diaporthe  parasitica  Murrill,  and  is  said  to  very  closely  re- 
semble the  parasite  found  in  Italy,  Endothia  radicalis.  This 
fungus  has  been  the  cause  of  very  great  destruction  of  chestnut 
trees  in  the  eastern  United  States.  When  any  of  the  spores  of 
this  fungus  gain  entrance  into  a  wound  on  any  part  of  the  tree, 
thread-like  mycelia  are  developed  in  the  inner  layers  of  the  bark, 
and  these  spread  concentrically  until  they  girdle  the  trunk  or 


FlG.  30.  Large  Chestnut  tree  partly  killed  by  the  bark  disease.  Note  branches 
in  the  center  either  killed  or  bearing  dwarfed  leaves,  and  the  other  larger  branches  still 
unaffected. — From  photograph  by  Haven  Metcalf. 

limb,  so  that  if  it  happens  that  the  trunk  is  affected  the  entire  tree 
may  die  within  the  year,  while  if  it  is  the  smaller  branches  which 
are  attacked,  only  those  parts  beyond  the  point  of  infection  are 
killed,  while  the  remainder  of  the  tree  will  survive  for  some 
years  (Fig.  30). 

When  the  bark  is  attacked  by  the  fungus  it  shows  minute,  more 
or  less  crater-like  spots  of  a  yellowish-orange  or  reddish-brown 


PRINCIPAL  GROUPS  OF  PLANTS 


55 


color  which  are  pustules  of  the  fruiting  fungus.  These  pustules 
produce  mostly  winter  spores  (ascospores),  although  occasionally 
a  long  strip  of  summer  spores  (conidia)  are  also  produced  (Figs. 
31  and  32). 


FlG.  31.  Typical  appearance  of  branches  of  Chestnut  tree  affected  with  chestnut 
blight.  At  left,  bark  showing  pustules  of  the  parasitic  fungus  bearing  winter  spores.  At 
right,  the  diseased  bark  showing  pustules  and  form  of  discharge  of  summer  spores  in  damp 
weather. — From  photograph  by  Haven  Metcalf. 

The  control  of  the  disease  over  large  districts  consists  mainly 
in  destroying  the  affected  trees  and  carefully  burning  the  rubbish. 


56  A  TEXT-BOOK  OF  BOTANY. 

Single  trees  are  treated  by  removing  the  affected  branches  and 
painting  over  the  cut  ends  with  coal  tar  to  prevent  reinfection. 

For  further  details  on  this  fungus  consult :  Murrill,  "  A  New 
Chestnut  Disease,"  Torreya,  Sept.,  1906;  Farmers'  Bulletin  467, 
U.  S.  Department  of  Agriculture;  Metcalf,  -"  Diseases  of  the 
Chestnut  and  Other  Trees,"  Trans.  Mass.  Hort.  Soc.,  August, 


FIG.  32.  Chestnut-blight  disease,  which  occurs  in  small  yellowish  pustules  the  size 
of  a  pin  head.  A,  section  of  pustule  showing  perithecia;  B,  asci  with  sporidia;  a,  usual 
form;  b,  form  rarely  found;  C,  sporidia;  D,  summer  spores.— After  Murrill. 

1912;  Farlow,  "Fungus  of  the  Chestnut-Tree  Blight,"  Science, 
May  10,  1912. 

BASIDIOMYCETES. — The  Basidiomycetes  are  the  most  highly 
organized  of  the  Fungi.  The  mycelium  consists  of  white  branch- 
ing threads  and  is  usually  concealed  in  the  substratum.  In  the 
cultivation  of  the  edible  mushrooms  propagation  is  by  means  of 
the  mycelium,  which  is  known  commercially  as  "  spawn."  It  is 
recognized,  however,  that  mushrooms  can  not  be  propagated  in 


PRINCIPAL  GROUPS  OF  PLANTS. 


57 


this  way  exclusively  for  more  than  two  or  three  years.  The  my- 
celium is  really  the  plant  body,  and  the  part  which  rises  above  the 
surface  and  is  commonly  regarded  as  the  toadstool  or  mushroom 
(Figs.  33  to  37)  is  a  fruit  branch,  or  spore-producing  organ. 
When  these  branches  first  make  their  appearance  they  are  in  the 
form  of  small  solid  bodies  known  as  "  buttons  "  (Fig.  33,  I-V). 


J 


FlG.  33.  Agaricus  campestris,  the  common  edible  mushroom,  showing  at  A  on  the 
left  mycelium  (m)  and  development  of  buttons  or  young  mushrooms;  I  to  V,  longitudinal 
sections  showing  successive  stages  in  development  of  fruit  body;  m,  mycelium;  st,  stipe; 
h,  portion  between  veil  (v)  and  spore-bearing  portion  (1). 

The  illustration  to  the  right  (A,  B,  C)  shows  the  structure  of  the  hymenium  in  different 
degrees  of  magnification:  A,  section  through  portion  of  pileus  showing  five  of  the  gills; 
B,  section  of  a  gill  somewhat  magnified;  C,  section  of  gill  still  more  magnified  and  showing 
sterile  cells  or  paraphyses  (q),  and  the  fertile  cells  or  basidia  (s),  from  each  of  which  arise 
two  basidiospores. — After  Sachs. 

As  growth  proceeds  these  bodies  differentiate  into  a  stalk-like 
portion  known  as  the  stipe  (Fig.  33,  st),  which  is  directly  con- 
nected with  the  mycelium,  and  an  umbrella-like  portion  borne  at 
the  summit  of  the  stalk,  called  a  pileus,  which  at  first  is  closed 
down  over  the  stalk,  but  later  expands  or  opens  more  or  less 
widely  according  to  the  species.  On  the  under  surface  of  the 
pileus,  known  as  the  hymenium,  the  spores  are  borne  (Fig.  33, 


(58 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  34.  Some  common  edible  mushrooms  and  a  common  poisonous  one.  The  fol- 
lowing are  edible:  i,  Common  Field  mushroom  (Agaricus  campestris);  3,  Clavaria  flava, 
young  plant;  6,  Puffball  (Lycoperdon  cyathiforme) ;  4,  Morel  (Morchella  esculenta);  5, 
Chanterelle  (Cantharellus  cibarius);  7,  Fairy-ring  Fungus  (Marasmius  oreades). 

Only  one  poisonous  species  is  shown,  namely,  2,  the  deadly  Agaric  (Amanita  phalloides). 
— Adapted  from  Farlow. 


PRINCIPAL  GROUPS  OF  PLANTS.  59 

A,  B,  C).  In  some  cases  the  under  surface  is  composed  of 
a  series  of  narrow,  radiating,  knife-like  plates,  or  gills,  as  in 
the  common  edible  mushroom  Agaricus.  On  the  surface  of 
the  gills  the  basidia  or  spore-bearing  organs  arise.  The  basidia 
are  somewhat  swollen  terminal  cells  of  the  closely  arranged  hyphse 
composing  the  gills,  which  bear  a  group  of  spores  on  short  stalks 
(Fig.  33,  C).  Both  the  basidia  and  spores  (basidio-spores)  are 
of  a  characteristic  size  and  number  for  the  different  species. 

Several  types  of  Basidiomycetes  are  usually  recognized,  de- 
pending on  the  manner  in  which  the  spores  are  borne. 

1.  The   Gill   Fungi    (Agaricacese),   in   which   the   spores   are 
borne  on  plates  or  gills  which  radiate  from  the  stem  to  the  edge 
of  the  cap. 

2.  The  Pore  Fungi   (Polyporaceae),  in  which  the  spores  are 
borne  in  tubes  or  pits  opening  by  pores  rather  than  on  gills. 

3.  The  Coral  Fungi   (Clavariacese),  in  which  the  Fungi  are 
coral-like  or  leaf-like,  the  surface  of  the  cap  or  its  branches  being 
smooth. 

4.  The  Leather  Fungi  (Thelephoracese),  in  which  the  spore- 
bearing  surface  is  smooth  or  slightly  wrinkled.     The  texture  is 
usually  leathery  or  papery. 

5.  The  Jelly  Fungi  (Tremellacese),  in  which  the  fruiting  sur- 
face is  smooth  and  the  cap  is  more  or  less  jelly-like  when  wet. 

6.  The  Puff  Balls    (Lycoperdacese),   in  which  the  cap  is  a 
closed  ball  which  breaks  open  at  maturity  to  release  the  enclosed 
spores. 

7.  The  Carrion  Fungi  or  Stink-horn  Fungi   (Phallaceae)   re- 
semble the  puffballs  when  young,  but  are  ruptured  longitudinally, 
the  spores  thereby  being  exposed  on  the  top  as  a  gelatinous  mass. 

Of  these  seven  groups  the  Gill  Fungi  are  the  commonest,  and 
one  or  two  types  will  be  considered,  namely,  the  common  edible 
mushroom  and  two  of  the  poisonous  group,  Amanita. 

Edible  Fungi. — Agaricus  campestris  (common  mushroom) 
(Figs.  33  and  34)  is  practically  the  only  edible  species  cultivated 
in  this  country.  The  plant  grows  wild  in  open  grassy  fields  dur- 
ing August  and  September.  It  is  not  found  in  the  mountains  to 
any  extent,  and  is  never  found  in  the  woods  or  on  trees  or  fallen 
trunks.  The  color  of  the  stipe  and  the  upper  surface  of  the 


6o 


A  TEXT-BOOK  OF  BOTANY. 


FlG.  35.  A  decaying  tree  trunk  showing  the  cause  of  the  death  of  the  tree  by  the 
appearance  of  the  several  fungi  (probably  Amanita  muscaria).  It  is  not  unusual  to  find 
trees  showing  signs  of  disease  and,  finally,  even  dying,  and  it  is  not  until  the  death  of  the 
tree  that  the  mature  fungus  makes  its  appearance.  For  some  years  the  mycelium  of  the 
fungus  has  been  working  its  way  into  the  tissues  not  only  of  the  bark  but  of  the  wood, 
sapping  it  of  its  vitality.  When  there  is  no  longer  any  food  supply  the  fungus  produces 
its  fruit;  the  spores,  being  scattered  by  either  the  wind  or  through  the  agency  of  birds, 
are  carried  to  other  trees  and  find  entrance  into  wounds,  where  they  germinate  and  repeat 
their  destruction. — From  a  photograph  by  Henry  Troth. 


PRINCIPAL  GROUPS  OF  PLANTS.  61 

pileus  varies  from  whitish  to  a  drab  color,  but  the  color  of  the 
gills  is  at  first  pinkish  and  then  of  a  brownish-purple,  which  is 
an  important  character,  the  color  being  due  to  the  spores.  The 
stipe  is  cylindrical  and  solid,  and  a  little  more  than  half  way  up 
is  furnished  with  a  membranous  band  known  as  the  ring.  There 
are  no  appendages  at  the  base  of  the  stipe,  which  appears  to  rise 


FIG.  36.  Edible  Boletus  (Boletus  edulis),  an  excellent  edible  mushroom  found  in  woods 
and  openings  in  summer  and  autumn.  The  cap  is  8  to  15  cm.  wide,  grayish-,  yellowish-,  or 
brownish-red,  sometimes  paler  toward  the  edge,  smooth,  and  more  or  less  convex;  flesh 
whitish  or  yellowish,  or  somewhat  reddish  just  beneath  the  skin;  stem  white,  stout,  and 
often  bulbous. — From  monograph  on  Minnesota  Mushrooms  by  Frederic  E.  Clements. 

directly  out  of  the  ground.  Before  the  pileus  is  fully  expanded  a 
veil  extends  from  its  border  to  the  stipe,  which  when  ruptured 
leaves  a  portion  attached  to  the  stipe,  and  it  is  this  which  consti- 
tutes the  ring.  The  ring  shrinks  more  or  less  in  older  specimens, 
but  usually  leaves  a  mark  indicating  where  it  has  been  formed. 

Poisonous  Fungi.— There  are  two  of  the  poisonous  group 
of  Fungi  which  are  very  common  and  which  have  some  resem- 


62  A  TEXT-BOOK  OF  BOTANY. 

blance  to  the  edible  mushroom  just  described,  namely,  the  fly 
agaric  (Amanita  muscaria)  (Fig.  38)  and  the  deadly  agaric 
(Amanlta  phalloides)  (Fig.  34).  The  fly  agaric,  while  more  abun- 
dant in  some  localities  than  the  common  edible  mushroom,  is 


FIG.  37.  Pale  Lenzites  (Lenzites  betulina),  a  non-edible  fungus  common  on  trunks 
and  stumps  throughout  the  year.  The  cap  is  whitish,  corky,  more  or  less  densely  hairy, 
and  marked  by  concentric  grooves;  the  stem  is  lacking  and  the  gills  are  whitish,  more  or 
less  branched  and  united. — From  monograph  on  Minnesota  Plant  Diseases  by  E.  M. 
Freeman. 

seldom  found  in  grassy  pastures,  but  more  generally  in  poor  soil,, 
especially  in  groves  of  coniferous  trees.  It  occurs  singly  and  not 
in  groups.  The  gills  are  always  white ;  the  stipe  is  white,  hollow, 
and  provided  with  a  ring  at  the  top,  and  the  base  is  bulbous,  hav- 
ing fringy  scales  at  the  lower  part.  The  pileus  is  yellow  or  orange 


PRINCIPAL  GROUPS  OF  PLANTS. 


PIG.  38.  Fly  Agaric  (Amanita  muscaria),  a  very  deadly  mushroom.  The  cap  is  bright 
red  or  orange,  becoming  yellow  or  even  whitish  in  age,  roughened  with  many  thick,  white 
angular  fragments  of  the  volva;  the  stem  is  stout,  white,  scaly,  bulbous,  and  hollow;  volva 
forming  several  concentric  scaly  rings  on  the  bulb;  gills  free  or  touching,  white  or  yellowish. 
This  is  frequent  in  woodland,  forest,  or  clearing  from  June  to  frost,  and  is  deadly  poisonous. 
—From  monograph  on  Minnesota  Mushrooms  by  Frederic  E.  Clements. 


64  A  TEXT-BOOK  OF  BOTANY. 

and  sometimes  reddish ;  the  surface  is  smooth,  with  prominent, 
angular,  warty  scales,  which  can  be  easily  scraped  off. 

The  deadly  agaric  (Fig.  34,  illus.  2)  somewhat  resembles  the 
fly  agaric  and  also  differs  from  the  common  mushroom  in  not 
usually  growing  in  pastures.  It  occurs  singly,  but  not  in  groups, 
in  woods  and  borders  of  fields.  The  gills  and  stipe  are  white, 
the  latter,  when  young,  having  a  number  of  mycelial  threads 
running  through  it.  The  base  is  quite  bulbous,  the  upper  part  of 
the  bulb  having  a  sac-like  membrane  called  the  volva.  The  pileus 
may  vary  from  any  shade  of  dull  yellow  to  olive,  although  some- 
times it  is  shiny  and  white.  -While  it  does  not  possess  the  warty 
scales  found  in  the  fly  agaric,  it  has  occasionally  a  few  mem- 
branous patches. 

The  Toxic  Principles  in  Poisonous  Fungi. — The  deadly 
agaric  (Amanita  phalloides)  is  the  cause  of  the  greatest  number 
of  cases  of  mushroom  poisoning.  According  to  Abel  and  Ford, 
it  contains  two  toxic  principles:  (i)  Amanita-hemolysin,  a  blood- 
laking  principle,  which  is  a  very  sensitive  glucoside, — that  is,  pre- 
cipitated by  alcohol,  destroyed  by  heating  to  70°  C.  and  by 
the  action  of  digestive  ferments;  (2)  Amanita-toxin,  which  is 
soluble  in  alcohol,  is  not  destroyed  by  the  action  of  heat  or 
ferments.  The  latter  principle  is  the  important  poisonous  prin- 
ciple in  mushroom  poisoning  and  is  probably  the  most  toxic 
principle  known,  0.4  of  a  milligramme  killing  a  guinea  pig  within 
24  hours.  "  The  majority  of  individuals  poisoned  by  the  '  deadly 
amanita  '  die,  but  recovery  is  not  impossible  when  small  amounts 
of  the  fungus  are  eaten,  especially  if  the  stomach  be  very  promptly 
emptied,  either  naturally  or  artificially." 

The  fly  agaric  (Amanita  muscaria)  owes  its  toxicity  to  mus- 
carine,  an  alcohol-soluble  crystalline  substance.  It  is  supposed 
by  Ford  that  the  fly  agaric  may  contain  another  poisonous  constit- 
uent. In  cases  of  poisoning  atropine  has  been  successfully  ad- 
ministered hypodermically  in  doses  of  y-J-g-  to  -£$  of  a  grain. 

It  is  stated  that  the  A.  muscaria,  used  by  the  peasants  of  the 
Caucasus  in  the  preparation  of  an  intoxicating  beverage,  is  deficient 
in  muscarine. 

The  question  as  to  whether  the  ordinary  edible  mushrooms, 
as  distinguished  from  the  poisonous  toadstools,  may  not  in  cer- 


PRINCIPAL  GROUPS  OF  PLANTS.  65 

tain  localities  or  at  certain  periods  of  the  year  be  the  cause  of 
fatal  intoxication  is  answered  by  Ford  in  the  negative.  He  states 
(Science,  30,  p.  105,  July  23,  1909)  that  there  are  no  authentic 
cases  of  poisoning  from  the  black  or  brown  spored  agarics, 
although  old  and  badly  decomposed  specimens  may  cause  transient 
illness. 

.Economic  Uses  of  Fungi. — A  large  number  of  the  Fungi, 
particularly  of  the  Basidiomycetes,  are  used  for  food.  There 
are,  however,  only  a  few  of  these  which  enter  the  market.  These 
are  derived  chiefly  from  Agaricus  campestris  (Figs.  33  and  34) 
and  Agaricus  arvenis,  although  some  other  species  of  Agaricus 
as  well  as  Morchella  esculenta  (Fig.  34,  illus.  4)  furnish  excellent 
products  and  are  cultivated  to  a  limited  extent.  The  "  truffles  " 
of  the  market  are  tuber-like  masses  formed  under  ground,  which 
consist  of  the  ascocarps  of  certain  Tuberacex,  one  of  the  sub- 
groups of  the  Ascomycetes,  and  which  are  used  as  a  condiment 
and  sometimes  roasted  like  potatoes.  Tuckahoe  or  "  Indian 
bread  "  is  also  produced  under  ground  and  consists  apparently 
of  the  fungus  Pachyma  Cocos  and  the  roots  of  Liquidambar,  the 
tissues  of  which  have  been  changed  into  a  compound  resembling 
pectic  acid  by  the  fungus.  Quite  a  number  of  Fungi  have  been 
used  in  medicine,  as  Claviceps  purpurea  (Fig.  29),  Polyporus 
officinalis  and  other  species,  and  various  species  of  Lycoperdon. 
A  number  of  species  are  used  in  making  surgeon's  agaric  (Fungus 
chirurgorum)  formerly  used  as  a  haemostatic,  including  Lycoper- 
don Bovista  and  Polyporus  fomentarius.  Many  of  them  yield  very 
toxic  principles,  as  ( i )  several  species  of  Amanita  which  contain 
several  toxic  principles;  (2)  Lactarius  piperatus  and  others 
which  yield  highly  poisonous  resinous  principles.  Other  uses  of 
Fungi  have  been  mentioned  under  the  several  groups. 

USTILAGINE^:  and  UREDINE^. — There  are  two  groups  of 
Fungi  of  considerable  economic  interest  which  by  some  writers 
are  classed  by  themselves,  and  by  others  placed  with  the  Basidio- 
myretes.  These  are  the  Ustilaginese,  or  Smut  Fungi,  and  the 
Uredinese,  or  Rust  Fungi. 

The  Smut  Fungi  are  parasitic  on  higher  plants.     The  myce- 
lium penetrates  the  tissues  of  the  host,  but  does  not  seem  to 
cause  either  disease  or  malformation  of  the  plant.    Injury  to  the 
5 


66 


A  TEXT-BOOK  OF  BOTANY. 


host  results  only  after  the  development  of  resting  spores.  The 
mycelia  are  hyaline,  more  or  less  branched,  and  finally  become 
septate.  They  send  short  branches,  called  haustoria,  into  the 
cells  of  the  host,  from  which  they  obtain  nourishment.  Eventu- 
ally the  mycelium  becomes  much  branched,  compact  and  more  or 
less  gelatinous  through  a  transformation  of  the  hyphal  walls, 
forming  gall-like  swellings  or  blisters  on  the  host.  Spores  are 
formed  within  this  gelatinous  mass  at  the  ends  of  the  branches 


.FlG.  39.     Corn   smut    (Ustilago   Maydis)    showing  several   gall-like   masses  of  smut  full 

of  spores. 

of  the  mycelium.  At  a  later  stage  the  smut  loses  its  gelatinous 
character,  the  mass  breaks  up,  and  the  spores  are  freed  and  dis- 
tributed as  a  dry,  dusty  powder.  The  spores  (primary  conidia) 
are  somewhat  spherical  or  ellipsoidal,  and  are  generally  separate, 
but  are  sometimes  united  into  a  mass  forming  the  so-called  "  spore 
balls."  These  are  resting  spores  and  upon  germination  (Fig.  40) 
produce  a  promycelium  or  basidium  which  becomes  septate  and 
from  each  cell  of  which  conidia  called  sporidia  arise.  The  sporidia 
are  formed  in  succession  one  after  another  and  the  process  con- 


PRINCIPAL  GROUPS  OF  PLANTS. 


67 


tinues  for  some  time.  On  germination  they  bud  like  yeast,  form- 
ing new  conidia,  or  when  nutrition  is  not  abundant  they  may 
form  a  mycelium,  which  is  usually  the  case  when  they  germinate 
on  a  host  plant. 

Corn    Smut. — One    of    the    Smut    Fungi,    namely,    Ustilago 
Maydis,  which  develops  on  Indian  corn  (Fig.  39),  is  used  in  medi- 


FIG.  40.  Spores  of  various  Smuts.  I,  Ustilago  longissima  growing  on  the  reed  meadow- 
grass  (Panicularia  americana);  2,  Ustilago  Maydis  from  Indian  corn  (Zea  Mays);  3,  Ustilago 
Oxalidis  on  the  yellow  wood-sorrel  (Oxalis  stricta) ;  4,  Ustilago  utriculosa  on  the  Pennsyl- 
vania persicaria  (Polygonum  pennsylvanicum). 

FlG.  4oa.  Germination  of  spores.  5,  Ustilago  utriculosa,  in  water,  showing  promy- 
celium  and  sporidia;  6,  Doassansia  opaca  from  the  broad-leaved  arrow-head  (Sagittaria 
lalifolia)  in  water,  showing  promycelium,  sporidia,  and  secondary  sporidia  which  are  falling 
off;  7,  Ustilago  Avenue  from  oat  (Avena  saliva)  in  horse  dung,  showing  promycelium,  and 
lateral  "infection  threads"  or  hyphas;  8,  germination  of  a  sporidium  of  Ustilago  Sorghi  into 
an  infection  thread;  9,  small  portion  of  a  group  of  sporidia  developed  from  promycelium 
of  Tolyposporium  eriocauli  in  potato  agar;  10,  cross-section  of  epicotyl  of  broom-corn  in- 
fected by  Ustilago  Sorghi  showing  mycelium  ramifying  through  parenchyma  cells  of  the 
cortex. — After  Clinton. 

cine.  It  forms  rather  large  gall-like  masses  on  all  parts  of  the 
plant,  including  the  root,  stem  and  leaves,  and  both  staminate  and 
pistillate  flowers.  The  spores  (Fig.  40)  are  at  first  a  dark  olive- 
green,  but  on  maturity  are  dark  brown.  They  are  sub-spherical, 
have  prominent  spines,  and  vary  from  8  to  15  microns  in  diameter. 
They  do  not  germinate  at  once,  but  on  keeping  them  for  six 


68 


A  TEXT-BOOK  OF  BOTANY. 


months  to  a  year  they  germinate  readily  on  a  culture  medium 
of  potato,  and  retain  their  power  of  germination  for  years 

Rust  Fungi. — The  Rust  Fungi  are  parasitic  on  higher  plants 


FIG.  41.  Wheat  rust  (Pucdnia  graminis).  A,  teleutospore  or  winter  spore  germinating 
and  giving  rise  to  a  promycelium  (p)  and  sporidia  (s);  B,  a  few  leaves  of  barberry  attacked 
by  sporidia  which  give  rise  to  the  aecidia;  C,  transverse  section  through  barberry  leaf  show- 
ing three  cup-like  receptacles  (aecidia)  on  the  lower  surface  of  the  leaf  containing  per- 
pendicular rows  of  conidia  (secidiospores) ;  D,  germinating  aecidiospore  on  wheat;  E, 
wheat  plant  attacked  by  aecidiospores  as  shown  by  the  elongated  blotches  on  the  leaves; 
F,  cross  section  of  leaf  of  wheat  showing  on  the  upper  surface  the  rust  spores  which  are 
breaking  through  the  epidermal  layer  (r);  G,  summer  spores  (uredospores) ;  H,  teleutospores 
or  winter  spores  formed  on  wheat  leaf. — After  Dodel-Port. 

and  produce  a  thread-like  branching,  cellular  mycelium,  which 
develops  in  the  tissues  of  the  host.  They  differ  especially  from  the 
other  Fungi  in  producing  resting  spores  known  as  TELEUTOSPORES.. 


PRINCIPAL  GROUPS  OF  PLANTS.  69 

These  spores  consist  of  one  or  more  cells  surrounded  by  a  thick 
black  wall,  and  they  produce  the  "black  rust"  seen  on  foliage 
at  the  end  of  the  season. 

Wheat  Rust. — The  most  important  member  of  the  Rust  Fungi 
is  Puccinia,  of  which  there  are  a  large  number  of  species  that  are 
destructive  to  economic  plants,  as  wheat,  plum,  cherry,  red  cur- 
rant, etc.  The  one  whose  life  history  has  been  best  studied  is  the 
wheat  rust  (Puccinia  graminis),  which  requires  two  different 
plants  to  complete  its  life  history,  namely,  wheat  and  barberry. 
The  Teleutospores,  or  "winter  spores"  (Fig.  41,  //),  as  they 
are  called,  because  of  their  carrying  the  life  of  the  plant  over  the 
winter  season,  consist  of  two  cells.  These  spores  exist  on  the 
leaves  and  stems  of  wheat  over  winter,  and  in  the  spring  they  ger- 
minate (Fig.  41,  A).  From  each  cell  a  mycelium  (promycelium 
or  basidium)  consisting  of  two  to  four  cells  arises  (Fig.  41,  A,  />), 
and  from  the  tip  of  each  branch  of  the  promycelium  a  spore 
known  as  a  sporidium  develops  (Fig.  41,  A,  s).  The  Sporidia 
are  scattered  by  the  wind,  and  when  they  fall  on  the  barberry 
leaves  (Fig.  41,  B)  they  germinate,  producing  a  dense  mass  or 
mycelium  which  penetrates  into  the  tissues  of  the  host. 

Sooner  or  later,  just  within  the  under  surface  of  the  leaf, 
there  is  formed  a  more  or  less  spherical,  dense  mass,  which  grows 
outward,  breaking  through  the  surface,  forming  a  cup-like  re- 
ceptacle known  as  an  aecidium  (Fig.  41,  C).  The  ^Ecidia,  or 
cluster  cups,  are  orange  or  yellow  and  are  filled  with  perpendicular 
rows  or  chains  of  spores  which  arise  from  the  basidium-like 
mycelium  below.  The  spores,  which  have  received  the  name 
JEcidiospores,  are  somewhat  spherical  or  polyhedral,  and  contain 
a  reddish-yellow  oil.  They  are  scattered  by  the  wind  and,  falling 
upon  the  wheat  plant  (Fig.  41,  £),  germinate  immediately,  form- 
ing a  dense  mycelium.  At  first  it  produces  what  is  known  as  a 
"  Summer  spore,"  or  Uredospore  (Fig.  41,  G),  giving  rise  to  the 
reddish-brown  spots  and  stripes  on  the  leaves  and  stalks  of  the 
wheat  plant.  The  Uredospores  are  i -celled,  and  are  carried  by 
the  wind  to  other  wheat  plants,  thus  rapidly  spreading  the  disease. 

The  Uredospores  arise  in  much  the  same  way  as  the  Teleuto- 
spores (Fig.  41,  //),  which  form  brown  patches  later  in  the  sea- 
son, and  which  have  been  already  considered.  The  Teleutospores 


70  A  TEXT-BOOK  OF  BOTANY. 

last  over  winter  on  the  old  wheat  plant,  and  in  the  spring  begin 
again  the  life-cycle  of  the  rust.  The  plant  which  results  from 
the  germination  of  a  teleutospore  gives  rise  to  sporidia,  which 
are  carried  to  the  barberry  leaves  where  secidiospores  are  pro- 
duced. The  latter  are  then  carried  to  growing  wheat,  forming 
first  uredospores  and  later  teleutospores.  It  should  be  remembered 
that  these  are  all  asexual  spores.  In  regions  where  there  are  no 
barberry  plants  to  act  as  host  the  aecidiospore  stage  is  omitted. 

THE  FUNGI  IMPERFECTI. — The  miscellaneous  fungi  included  in 
this  group  are  of  importance  because  of  the  great  damage  which 
they  cause  to  agricultural  crops.  The  potato  scab  is  an  especially 
destructive  pest  in  New  England  and  in  Canada.  The  scab  not  only 
develops  on  the  growing  tubers  in  the  soil,  but  can  be  spread  from 
a  few  affected  potatoes  to  a  whole  bin  of  clean  ones  if  they  come 
in  contact  with  them.  Prevention  of  this  disease  usually  consists 
in  disinfecting  the  tubers  which  are  used  for  seed  so  as  not  to 
carry  the  minute  organisms  into  the  soil. 

A  disease  affecting  the  leaves  of  the  potato  and  thereby  destroy- 
ing the  crop  is  due  to  a  fungus  whose  spores,  settling  on  the  leaves, 
germinate  and  penetrate  to  the  interior  through  the  stomata, 
finally  weakening  or  killing  the  plant. 

Some  of  the  other  important  forms  produce  a  pink  mold  on 
apples,  scabs  on  peaches  and  other  fruits,  mold  on  onions  and 
other  garden  crops.  The  blight  of  ginseng  and  the  blight  of 
cotton,  the  dry  rot  of  various  vegetables  and  the  blotches  on  many 
of  our  common  fruits  can  be  traced  to  the  development  of  these 
fungi.  The  study  of  these  forms  is  a  very  difficult  one,  and  re- 
searches are  constantly  being  carried  on  at  the  government  experi- 
ment stations,  as  well  as  by  individual  workers. 

For  a  description  of  these  forms,  as  well  as  many  other 
harmful  fungi,  consult  "  Fungous  Diseases  of  Plants,"  by  Duggar. 

DETECTION  OF  FUNGUS  IN  HOST. — Unless  special  means  are 
employed,  it  is  ofttimes  rather  difficult  to  trace  the  mycelial  of  the 
fungus  in  among  the  cells  of  the  host  plant.  Vaughan  (Annals 
of  the  Missouri  Botanical  Garden,  1914,  p.  241)  has  used  the  stain 
known  as  "  Pianeze  Illb  "  in  differentiation  of  the  fungus  from 
the  plant  substratum.  The  host  tissue  stains  green  and  the  my- 
celium a  deep  pink.  This  stain,  devised  by  Dr.  Pianeze  for  the 


PRINCIPAL  GROUPS  OF  PLANTS.  71 

study  of  cancer  tissue,  is  made  up  as  follows :  Malachite  green, 
0.50  Gm. ;  acid  fuchsin,  o.io  Gm. ;  "  Martius  gelb,"  o.oi  Gm. ; 
water  distilled,  150.00  c.c. ;  alcohol  (95  per  cent.),  50.00  c.c.  For 
use  with  plant  tissues  the  procedure  is  as  follows :  Wash  in  water 
or  alcohol,  stain  in  the  undiluted  mixture  15  to  45  minutes,  remove 
excess  stain  in  water,  and  decolorize  in  95  per  cent,  alcohol  to 
which  a  few  drops  of  hydrochloric  acid  have  been  added.  For  per- 
manent mounts,  clear  with  a  carbol-turpentine  mixture,  remove 
clearing  solution,  and  mount  in  balsam. 

This  stain  is  also  valuable  for  staining  spores  which  have  been 
allowed  to  germinate  on  the  surfaces  of  leaves.  In  such  cases 
the  killing  and  tissue-clearing  mixture  proposed  by  Duggar  is 
recommended,  viz.,  consisting  of  equal  parts  of  glacial  acetic 
acid  and  alcohol.  In  the  study  of  the  rusts,  the  best  results  are 
obtained  by  the  use  of  Durand's  combination  of  Delafield's  haema- 
toxylin  and  eosin  (Phytopathology,  1911,  p.  129). 

LICHENS. 

General  Characters. — The  Lichens  are  a  peculiar  group  of 
plants  in  that  an  individual  lichen  consists  of  both  an  alga  called 
a  GONIDIUM  and  a  fungus.  These  are  so  intimately  associated  that 
they  appear  to  be  mutually  beneficial,  and  such  a  relation  is  known 
as  SYMBIOSIS  (Fig.  42).  The  Algae  which  may  be  thus  associated 
in  the  Lichens  are  those  members  of  the  Blue  and  Green  Algae 
which  grow  in  damp  places,  as  Pleurococcus,  Nostoc,  Lyngbya, 
etc.  (Fig.  42).  The  Fungi  which  occur  in  this  relation  belong 
both  to  the  Ascomycetes  and  Basidiomycetes,  and  it  is  on  the 
characters  of  the  fruit  bodies  of  these  particular  Fungi  that  the 
main  divisions  of  Lichens  are  based.  The  Fungi,  however,  are 
not  known  to  exist  independently  of  the  Algae  with  which  they 
are  associated ;  that  is,  the  mycelia  of  the  fungi  will  not  live  for 
any  length  of  time  unless  they  come  in  contact  with  suitable 
algae.  In  its  development  the  fungus  forms  a  mycelium  which 
encloses  the  alga,  the  growth  of  which  latter  is  not  hindered.  The 
two  organisms  then  continue  to  grow  simultaneously,  forming 
lichen  patches.  A  section  of  a  lichen  shows  a  differentiation  into 
several  parts  (Fig.  43)  :  a  more  or  less  compact  row  of  cells  on 
both  surfaces  forming  two  epidermal  layers ;  and  an  inner  portion 


72  A  TEXT-BOOK  OF  BOTANY. 

made  up  of  the  hyphal  tissue  of  the  fungus  in  which  the  alga  is  em- 
bedded either  in  a  single  layer  or  throughout  the  mycelium.  The 
mode  of  growth  and  branching  is  influenced  largely  by  the  fungus, 
although  in  some  cases  the  alga  may  exert  the  most  influence.  In 
some  cases  the  lichen  consists  of  a  thallus  which  is  irregular  in 
outline,  growth  taking  place  at  no  definite  point,  and  in  other 
cases  branches  which  are  more  or  less  regular  are  formed,  growth 
taking  place  at  the  apex. 


FIG.  42.  Lichens  showing  manner  of  union  of  algae  or  gonidia  (g)  and  hyphas  (h)  of 
Fungi.  A,  Protococcus,  showing  the  manner  in  which  hyphae  penetrate  the  cell  and  in- 
fluence cell  division;  B,  Scytonema,  an  alga  surrounded  by  richly  branching  hyphas;  C,  chain 
of  Nostoc  showing  hypha  of  fungus  penetrating  a  large  cell  known  as  a  heterocyst;  D,  fungal 
hyphae  have  penetrated  the  cells  of  Glceocapsa,  a  blue-green,  unicellular  alga;  E,  Chlorococcum, 
a  reddish  or  yellowish  alga  found  in  Cladonia  furcata,  the  cells  of  which  are  surrounded  by 
the  short  hyphae  of  the  fungus. — A,  after  Hedlund;  B-E,  after  Bornet. 

The  walls  of  the  hyphae  of  the  fungus  comprising  Lichens  con- 
sist at  first  of  pure  cellulose.  In  older  material  the  walls  undergo 
more  or  less  modification,  being  changed  in  part  to  starch,  mucilage, 
or  fixed  oil.  There  may  be  also  infiltrated  among  the  layers  of 
the  wall  calcium  oxalate,  the  latter  constituent  being  especially 
characteristic  of  the  crustaceous  Lichens.  The  most  interesting 
constituents  of  Lichens  are  the  coloring  principles,  which  are 
mostly  of  an  acid  character  and  are  termed  Lichen-acids.  They 


PRINCIPAL  GROUPS  OF  PLANTS.  73 

give  very  striking  reactions  with  solutions  of  the  alkalies  and  solu- 
tions containing  chlorine.  The  reaction  with  iodine  solutions  is 
also  employed  for  diagnostic  purposes ;  some  of  the  Lichens  give 
a  blue  reaction,  while  others  behave  like  amylo-dextrin. 

Groups  of  Lichens. — According  to  the  manner  of  growth 
and  the  manner  of  attachment  to  the  substratum,  three  principal 
groups  of  Lichens  may  be  distinguished :  namely,  ( i )  Crus- 
taceous  Lichens,  where  the  thallus  adheres  closely  to  the  stones 
and  barks  of  trees  and  practically  can  not  be  removed  without 
injury;  (2)  Foliose  Lichens,  or  those  which  are  more  or  less 
flattened,  somewhat  leaf-like  and  attached  at  different  points;  (3) 
Fruticose  Lichens,  or  those  which  are  attached  at  a  particular 
part  of  the  thallus,  and  form  diffusely  branching  clumps.  To  this 
latter  group  belong  Cetraria  islandica  or  Iceland  moss  (Fig.  43), 
which  is  used  in  medicine,  Usnea  barbata  and  the  red-fruiting 
Cladonias  which  are  so  common. 

Reproduction  in  the  Lichens  takes  place  in  several  ways.  In 
all  of  them  there  is  a  vegetative  mode  by  means  of  what  are 
known  as  SOREDIA.  These  are  small  spherical  bodies  consisting  of 
a  group  of  algal  cells,  which  are  surrounded  by  a  mass  of  hyphae, 
and  which  when  cut  off  from  the  main  body  are  able  to  grow. 
Lichens  also  produce  spores  of  a  number  of  kinds.  In  the  largest 
group,  the  one  to  which  Cetraria  islandica  (Fig.  43)  belongs,  the 
spores  are  found  in  special  spherical  receptacles,  known  as  PYC- 
NIDIA,  which  are  formed  on  the  teeth  of  the  margin  of  the  thallus. 
The  spores  arise  from  the  ends  of  hyphse  at  the  base  of  the  pyc- 
nidia  and  are  in  the  nature  of  conidiospores.  To  these  spores 
the  name  PYCNOCONIDIA  has  been  applied.  Cetraria  also  pro- 
duces, like  many  other  Lichens,  disk-like  or  cup-shaped  bodies  at 
various  places  on  the  surface  of  the  thallus,  which  are  known  as 
APOTHECIA  and  which  may  be  regarded  as  exposed  or  open  asco- 
carps.  The  inner  surface  of  the  apothecia  is  lined  with  a  number 
of  asci  as  well  as  sterile  cells,  the  former  giving  rise  to  ascospores. 

Economic  Uses  of  Lichens. — A  number  of  the  Lichens  are 
used  in  medicine,  as  several  species  of  Cetraria,  Pertusaria  corn- 
munis,  Physica  parietina,  Sticta  pulmonacea,  Evernia  furfuracea. 
Some  of  those  used  in  medicine  are  also  used  as  foods  on  account 


74 


A  TEXT-BOOK  OF  BOTANY. 


of  the  gelatinous  carbohydrate  lichenin  which  they  contain.  Be- 
sides those  given,  the  following  may  be  mentioned :  Cladonia 
rangiferina  (reindeer  moss),  Lecanora  esculenta  (supposed  to  be 
the  manna  of  the  Israelites).  The  Lichens  are,  however,  chiefly 
of  interest  because  of  the  coloring  principles  which  they  contain. 


FIG.  43.  Iceland  Moss  (Cetraria  islandica).  A-F,  various  forms  of  thalli  showing 
apothecia  (a);  I,  cross-section  of  an  apothecium  showing  the  hymenium  (h),  the  hypothe- 
cium  (p),  the  algal  layer  (e),  the  medullary  layer  (m),  and  lower  or  ventral  surface  (1);  K, 
an  ascus  with  eight  ascospores  and  two  paraphyses  from  the  hymenium  (h). 

Roccella  tinctoria,  Lecanora  tartarea,  and  other  species  of  Leca- 
nora, yield  upon  fermentation  the  dyes  orcein  and  LITMUS,  the 
latter  of  which  finds  such  general  use  as  an  indicator  in  volu- 
metric analysis.  Cudbear,  a  purplish-red  powder,  is  prepared  by 
treating  the  same  lichens  with  ammonia  water ;  while  in  the  prep- 


PRINCIPAL  GROUPS  OF  PLANTS.  75 

aration  of  orchil,  a  purplish-red  pasty  mass,  sulphuric  acid  and 
salt  are  subsequently  added.  A  number  of  species  contain  a  yel- 
low coloring  principle,  as  Zeora  sulphur ea,  Zeora  sordida,  Lecidca 
geographica  and  Opcgrapha  epigcca. 

ARCHEGONIATES. 

The  two  main  features  which  distinguish  the  Archegoniates 
from  the  Thallophytes  are  the  structure  of  the  sexual  organs  and 
the  distinct  manner  in  which  the  peculiar  phases  known  as  alter- 
nation of  generations  are  shown.  The  antheridium  or  male  sexual 
organ  is  a  well  differentiated  multicellular  body  which  is  either 
sunk  in  the  adjacent  tissues  of  the  plant  or  is  provided  with  a 
stalk.  Within  it  are  organized  the  sperms  or  spermatozoids,  which 
are  ciliate  and  swim  freely  in  water.  Corresponding  to  the  oogo- 
nium  of  the  Thallophytes  is  the  ARCHEGONIUM  or  female  sexual 
organ  which  gives  name  to  the  group.  The  archegonium  is  a 
flask-shaped  cellular  body  consisting  of  a  basal  portion  of  venter, 
which  contains  a  single  egg,  and  a  neck  through  which  the  sperms 
enter  (Figs.  49  and  51). 

In  the  life  history  of  this  group  of  plants  there  are  two  gen- 
erations or  phases  of  development.  During  one  stage  the  arche- 
gonium and  antheridium  are  developed,  and  this  is  known  as  the 
sexual  generation,  and  as  these  organs  give  rise  to  gametes  or 
sexual  cells  it  is  also  spoken  of  as  the  GAMETOPHYTE.  By  the  union 
of  the  sex  cells  (sperm  and  egg)  an  oospore  is  formed  which 
germinates  at  once  within  the  archegonium.  That  portion  of  the 
plant  which  develops  from  the  oospore  gives  rise  to  asexual 
spores,  and  hence  this  phase  is  called  the  asexual  generation. 
It  is  also  spoken  of  as  the  SPOROPHYTE  from  the  fact  that  it  gives 
rise  to  spores.  These  spores  are  in  the  nature  of  resting  spores 
and  do  not  germinate  on  the  plant  as  does  the  oospore.  They  are 
distributed  and  on  germination  give  rise  to  the  gametophyte  stage. 

In  some  of  the  Archegoniates  these  two  phases  are  combined 
in  one  plant,  as  in  the  Bryophytes,  whereas  in  other  members  of 
the  group  the  two  phases  are  represented  by  two  distinct  plants ; 
that  is,  the  gametophyte  and  sporophyte  become  independent  of 
each  other,  as  in  the  Ferns. 


76 


A  TEXT-BOOK  OF  BOTANY. 


The  following  table  shows  the  main  divisions  and  subdivisions 
of  the  Archegoniates : 

Bryophytes..    ,   {Hepatic*  (Liverworts). 

J  f  J  \       -71     If  •  /    -l     yp 

[Musci  (Mosses). 


Archegoniates 


Pteridophytes .  . 


Filicales  (Ferns). 
Equisetales  (Horsetails). 
Lycopodiales  (Club  Mosses) 


BRYOPHYTES 


The  structure  of  the  sexual  organs  in  the  Liverworts  (Fig.  44) 
and  Mosses  (Fig.  49)  is  essentially  the  same,  but  the  vegetative 
organs  are  more  or.  less  dissimilar.  In  the  Liverworts  the  plant 


FIG.  44.  A  common  moss  (Funaria).  A,  germinating  spores:  v,  vacuole;  w,  root- 
hair;  s,  exospore.  B,  protonema  about  three  weeks  after  germination:  h,  procumbent 
primary  shoot;  b,  ascending  branch  of  limited  growth;  K,  bud  or  rudiment  of  a  leaf -bearing 
axis  with  root-hair  (w). — After  Sachs. 

body  or  thallus  lies  more  or  less  close  to  the  substratum  or  rises 
somewhat  obliquely,  whereas  in  the  Mosses  the  part  we  designate 
as  the  plant  is  in  all  cases  an  upright  leafy  branch.  The  moss 
plant  is  said  to  have  a  radial  structure  from  the  fact  that  the 
leaves  radiate  from  a  central  axis,  while  in  the  Liverworts  the 
thallus  is  dorsiventral ;  that  is,  as  a  result  of  its  habits  of  growth, 
it  is  characterized  by  having  a  distinct  upper  and  lower  surface. 


PRINCIPAL  GROUPS  OF  PLANTS. 


77 


The  Life  History  of  this  group  of  plants  may  probably  be 
best  illustrated  by  following  that  of  a  moss  plant.  Beginning 
with  the  germination  of  an  asexual  spore  which  is  microscopic  in 
size  and  which  germinates  on  damp  earth,  there  is  produced  an 


FIG.  45.  A  common  moss  (Polytrichum  gracile).  A,  showing  leafy  branches  (gameto- 
phores)  two  of  which  bear  sporogonia,  a  detached  sporogonium  (sporophyte)  with  sporan- 
gium from  which  the  calyptra  (ca)  has  been  detached.  B,  longitudinal  section  through  a 
nearly  ripe  sporangium  showing  columella  (o),  the  elongated  area  of  sporogenous  tissue 
(archesporium)  on  either  side,  annulus  (n),  peristome  (p),  lid  or  operculum  (u);  C,  trans- 
verse section  of  sporangium  showing  columella  in  center  and  dark  layer  of  sporogenous 
tissue  (archesporium);  D,  ripe  sporangium  (capsule)  showing  the  escape  of  spores  after 
detachment  of  lid;  E,  ripe  spore  containing  large  oil  globules;  F,  ruptured  spore  showing 
separated  protoplasm  and  oil  globules;  G.  two  germinating  spores  14  days  after  being  sown, 
showing  beginning  of  protonema  in  which  are  a  number  of  ellipsoidal  chloroplasts. — After 
Dodel-Port. 


78  A  TEXT-BOOK  OF  BOTANY. 

alga-like  body  consisting  of  branching  septate  filaments,  which  is 
known  as  the  PROTONEMA,  or  prothallus  (Fig.  44).  The  Proto- 
nema  lies  close  to  the  surface  of  the  ground  and  is  more  or  less 
inconspicuous  except  for  the  green  color.  From  the  lower  por- 
tion thread-like  processes,  or  rhizoids  consisting  of  a  row  of  cells, 
are  developed,  which  penetrate  the  ground.  Sooner  or  later  lateral 
buds  arise  from  some  of  the  lower  cells.  Growth  continues  from 
an  apical  cell  which  divides  and  gives  rise  to  cells  that  differentiate 
into  stem  and  leaves,  forming  an  upright  branch,  which  consti- 
tutes the  structure  commonly  regarded  as  the  "  moss  plant  "  (Fig. 
45,  A).  The  leaf-bearing  axis  varies  considerably  in  size;  in 
some  cases  it  is  but  a  millimeter  high,  whereas  in  some  species,  as 
Polytrichum  (Fig.  45),  it  may  be  several  hundred  millimeters  in 
height.  At  the  tip  of  the  branch  the  antheridium  (Fig.  49,  A) 
and  archegonium  (Fig.  49,  B)  are  formed.  These  organs  are 
developed  in  among  the  leaves  and  certain  hairy  processes,  known 
as  paraphyses  ( Fig.  49,  p) .  They  may  both  occur  at  the  end  of  one 
branch  (Fig.  49,  C)  or  they  may  occur  on  separate  branches 
(Fig.  49,  D),  when  the  plants  are  said  to  be  monoecious,  whereas 
when  these  organs  occur  on  separate  plants  (Fig.  49,  At  B)  the 
plants  are  called  dioecious.  In  the  case  of  dioecious  plants  the 
plant  bearing  the  antheridium  is  frequently  smaller  and  less  com- 
plex than  the  one  producing  the  archegonium.  As  already  stated, 
the  archegonium  produces  the  egg-cell  or  female  gamete  (egg) 
and  the  antheridium,  the  sperm  cell  or  male  gamete  (sperm). 

The  sperms  in  the  Bryophytes  are  more  or  less  filiform  and 
are  provided  with  a  pair  of  cilia  at  one  end.  The  antheridia, 
towing  to  the  peculiar  mucilaginous  character  of  the  cells,  only 
open  when  there  is  an  abundance  of  moisture,  when  the  sperms 
are  discharged  and  move  about  in  the  water,  some  being  carried 
to  the  archegonium,  which  likewise  opens  only  in  the  presence  of 
moisture.  With  the  transferral  of  the  sperms  to  the  archegonium 
and  the  union  of  one  of  these  with  the  egg  which  remains  sta- 
tionary, the  work  of  the  garnet ophyte  may  be  said  to  be  com- 
pleted. The  act  of  union  of  the  egg  and  sperm  is  known  as 
FERTILIZATION,  and  when  this  is  effected  the  next  phase  of  the 
life  history  begins. 

The  egg  after  fertilization  divides  and  re-divides  within  the 


PRINCIPAL  GROUPS  OF  PLANTS.  79 

archegonium,  which  becomes  somewhat  extended  until  finally  it 
is  ruptured.  The  dividing  cells  differentiate  into  a  stalk  and  a 
spore  case  or  sporangium  which  is  borne  at  the  summit,  the  whole 
structure  being  known  as  the  SPOROGONIUM  (Fig.  45).  The 
base  of  the  stalk  is  embedded  in  the  apex  of  the  moss  plant, 
and  is  known  as  the  foot,  it  being  in  the  nature  of  a  hausto- 
rium  or  nourishing  organ.  As  the  sporogonium  develops  and 
rises  upward  it  carries  with  it  the  ruptured  archegonium  which 
forms  a  kind  of  covering  over  the  top,  called  the  calyptra 
(Fig.  45,  ca).  At  first  the  sporangium  is  more  or  less  uniform, 
but  eventually  differentiates  into  two  kinds  of  tissues,  the  one 
being  sterile  and  the  other  fertile  (producing  spores),  which  latter 
is  known  as  the  ARCHESPORIUM  (Fig.  45,  B,  C).  The  fertile  tissue 
in  both  the  Liverworts  and  Mosses  is  variously  disposed ;  some- 
times it  forms  a  single  area  and  is  dome  shaped,  spherical,  or 
in  the  form  of  a  half  sphere.  In  other  cases  it  is  separated  into 
two  areas  by  sterile  tissue.  The  sterile  tissue  which  extends  up 
into  the  dome-shaped  archesporium,  or  which  in  other  cases 
separates  the  fertile  tissue  into  two  parts,  is  known  as  the 
columella  (Fig.  45,  B,  C).  The  sporangium  in  the  mosses  is 
capsule-like  and  the  spores  are  distributed  in  three  ways :  ( i ) 
In  some  cases  the  capsule  does  not  open,  but  when  it  decays  the 
spores  are  liberated.  (2)  In  other  cases  the  capsule  dehisces 
longitudinally  in  dry  weather,  and  thus  the  spores  are  freed. 
(3)  There  is  a  third  method  in  which  the  capsule  is  provided 
with  a  lid  or  operculum  which  comes  off  and  permits  the  spores 
to  escape,  this  being  the  most  common  method  for  the  escape 
of  the  spores  (Fig.  45,  D).  In  the  latter  instance  the  mouth 
of  the  capsule  is  usually  marked  by  one  or  two  series  of  cells, 
constituting  the  PERISTOME,  which  are  teeth-like  and  characteristic 
for  some  of  the  groups  of  mosses.  These  teeth  bend  inward  or 
outward,  according  to  the  degree  of  moisture,  and  assist  in  regu- 
lating the  dispersal  of  the  spores.  In  the  sphagnum  mosses  there 
is  no  peristome,  but,  owing  to  unequal  tension  of  the  lid  and  capsule 
on  drying,  the  lid  is  thrown  off,  and  the  spores  are  sometimes 
discharged  with  considerable  force  and  sent  to  quite  a  distance 
(as  much  as  10  centimeters),  in  this  way  insuring  their  dispersal. 
The  spores  (Fig.  45,  E)  vary  in  diameter  from  10  to  20 


8o  A  TEXT-BOOK  OF  BOTANY. 

microns,  being  sometimes  larger.  They  occur  in  groups  of  four 
in  a  mother-cell,  and  the  spore-group  is  known  as  a  tetrad,  which 
is  characteristic  for  the  Bryophytes  and  the  higher  groups  of 
plants.  The  spores  therefore  vary  in  shape  from  spherical  tetra- 
hedrons to  more  or  less  spherical  bodies,  depending  upon  the 
degree  of  separation.  The  contents  are  rich  in  protoplasm  and 
oil  (Fig.  45,  F).  The  wall  consists  of  two  layers,  the  outer  of 
which  is  either  yellowish  or  brown  and  is  usually  finely  sculptured. 
At  the  time  of  germination  the  outer  wall  is  thrown  off,  and  the 
protonema  develops  (Fig.  45,  G).  The  spores  may  germinate 
almost  immediately,  or  only  after  a  considerable  period.  These 
spores  are  asexual  and  each  one  is  capable  of  giving  rise  to  a 
new  plant.  With  the  formation  and  dispersal  of  the  spores  the 
work  of  this  generation  terminates,  and  this  phase  is  called  the 
sporophyte  or  asexual  generation,  from  the  fact  that  it  produces 
spores. 

Having  thus  followed  the  stages  of  development  in  the  life 
history  of  a  moss,  we  see  that  it  is  composed  of  the  following 
parts:  (i)  The  alga-like  protonema;  (2)  the  leafy  branch  which 
gives  rise  to  an  oospore  (sexual  spore),  and  (3)  the  sporogonium 
which  produces  asexual  spores.  The  leafy  branch  is  sometimes 
spoken  of  as  the  gametophore  (gamete-bearer),  and  it  and  the 
protonema  together  constitute  the  gametophyte  or  sexual  gen- 
eration, while  the  sporogonium  represents  the  sporophyte  or 
asexual  generation. 

The  protonema  sooner  or  later  dies  off  in  most  plants,  but  in 
other  cases  it  persists,  forming  a  conspicuous  portion  of  the 
gametophyte. 

HEPATIC^. 

General  Structure. — The  Hepaticse  or  Liverworts  (Fig.  46) 
are  usually  found  in  moist  situations.  The  protonema  formed  on 
germination  of  a  spore  is  filiform,  and  the  plant  body  which 
develops  from  it  consists  of  a  flat,  dichotomously-branching 
thallus,  or  it  may  in  some  of  the  higher  forms  differentiate  into 
a  leafy  branch,  as  in  the  leafy  liverworts.  The  thallus,  owing  to 
its  position,  has  an  upper  and  an  under  surface  which  are  some- 
what different,  as  in  Marchantia  (Fig.  46),  hence  it  is  said  to  be 


PRINCIPAL  GROUPS  OF  PLANTS. 


81 


DORSIVENTRAL.  From  the  lower  colorless  surface  unicellular 
rhizoids  arise  (Fig.  47,  h).  The  upper  surface  consists  of  several 
layers  of  cells  containing  chlorophyll  which  give  the  green  color 
to  the  plant. 

Vegetative  propagation  may  ensue  by  the  lower  portion  of 
a  branch  dying  and  the  upper  portion  continuing  as  an  inde- 
pendent plant.  Or  special  shoots,  known  as  GEMMAE,,  may  arise 


FIG.  46.  Dichotomously  branching  thallus  of  the  common  liverwort  (Marchantia 
Polymorpha)  showing  near  some  of  the  margins  the  cup-like  depressions  in  which  gemmae 
are  borne  (c),  and  several  archegoniophores  (a). 

either  on  the  margin  of  the  thallus  or  in  peculiar  cupules,  which, 
when  detached  by  rain  or  other  means,  are  capable  of  growing 
and  producing  a  new  plant. 

In  addition  the  thallus  body  produces  both  antheridia  and  arch- 
egonia  (Fig.  46)  which  may  arise  on  special  stalks  above  the  sur- 
face.   After  fertilization  of  the  egg-cell,  which  completes  the  work 
of  the  sexual  generation  of  gametophyte,  the  sporophyte  develops, 
6 


82 


A  TEXT-BOOK  OF  BOTANY. 


producing  a  sporogonium  consisting  of  a  short  stalk  which  is 
embedded  in  the  tissues  of  the  gametophyte,  and  a  capsule  (spor- 
angium). The  latter  at  maturity  dehisces  or  splits  and  sets  free 
the  spores,  which  are  assisted  in  their  ejection  by  spirally  banded 
cells  called  "  elaters  "  (Fig.  48,  C-F).  The  spores  on  germination 
give  rise  to  a  protonema  which  then  develops  a  thallus  bearing  the 
sexual  organs.  As  in  the  mosses,  the  sporogonium  represents  the 
asexual  generation  known  as  the  sporophyte. 

Liverwort  Groups. — There  are  three  important  groups  of 


chl 


FIG.  47.  Transverse  section  through  the  thallus  of  Marchantia  Polymorpha.  A, 
middle  portion  with  scales  (b)  and  rhizoids  (h)  on  the  under  side;  B,  margin  of  the  thallus 
more  highly  magnified,  showing  colorless  retieulately  thickened  parenchyma  (p),  epidermis 
of  the  upper  side  (o),  cells  containing  chlorophyll  (chl),  air  pore  (sp),  lower  epidermis  (u). 
—After  Goebel. 

Liverworts:  (i)  The  MARCHANTIA  Group  (Fig.  46),  in  which 
the  thallus  is  differentiated  into  several  layers  and  so  somewhat 
thickened.  Another  character  is  the  diversity  in  form  of  the 
sexual  organs,  which  range  from  those  which  are  quite  simple  to 
those  which  are  highly  differentiated.  In  Riccia  the  sexual  organs 
are  embedded  on  the  dorsal  (upper)  side  of  the  thallus,  while  in 
Marchantia  they  are  borne  upon  special  shoots,  one,  which  has  a 
disk  at  the  apex  that  bears  the  antheridia,  known  as  the  antheridio- 
phore,  and  another  whose  summit  consists  of  a  number  of  radiate 


PRINCIPAL  GROUPS  OF  PLANTS.  83 

divisions  and  bears  the  archegonia  (Fig.  46)  on  the  lower  sur- 
face, known  as  the  archegoniophore ;  these  being  borne  on  separate 
plants.  In  Riccia,  the  simplest  of  the  Liverworts,  the  sporangium 
is  enclosed  by  the  thallus  and  the  spores  are  not  liberated  until  the 
decay  of  the  plant. 

(2)   The   JUNGERMANIA    Group,    known    as    "  Leafy    Liver- 
worts "  or  "  scale  mosses,"  includes  those  forms  which  are  more 


FIG.  48.  Anthoceros  gracilis,  one  of  the  liverworts.  A,  thallus  with  4  sporogonia; 
B,  a  ripe  elongated  sporogonium,  dehiscing  longitudinally  and  showing  two  valves  between 
which  is  the  slender  columella;  C,  D,  E,  F,  various  forms  of  elaters;  G,  spores. — After 
Schiffner. 

or  less  moss-like  and  develop  stems  and  small  leaves.  The  sporo- 
gonium has  a  long  stalk  and  the  capsule  is  4-valved,  i.e.,  separates 
into  four  longitudinal  sections  at  maturity. 

(3)  In  the  ANTHOCEROS  Group  (Fig.  48)  the  gametophyte 
is  thallus-like  and  very  simple  in  structure,  the  sexual  organs  being 
embedded  in  the  thallus.  The  sporogonium  is  characterized  by  a 
bulbous  foot  and  an  elongated,  2-valved  capsule.  Like  the  thallus, 


84  A  TEXT-BOOK  OF  BOTANY. 

it  develops  chlorophyll  and  possesses  stomata  resembling  those 
found  in  certain  groups  of  mosses  and  higher  plants. 

MUSCI. 

in  the  Mosses  the  archegonia  always  form  the  end  of  the 
axis  of  a  shoot,  whether  this  be  a  main  one  or  a  lateral  one.  As 
has  already  been  stated  (p.  78),  the  sexual  organs  are  surrounded 
by  leaves  or  leaf-like  structures,  known  as  perichaetia  or  peri- 
chsetal  leaves,  and  by  hair-like  structures  or  paraphyses,  both  of 
which  are  considered  to  act  as  protective  organs.  Sometimes 
the  groups  of  sexual  organs  together  with  the  protective  organs  are 
spoken  of  as  the  "  moss  flower."  As  already  stated,  the  Mosses 
are  both  monoecious  (Fig.  49,  C,  D)  and  dioecious  (Fig.  49,  A, 
B),  hence  a  moss  flower  may  contain  only  one  of  the  sexual  organs 
or  it  may  contain  both.  Mosses  are  also  characterized  by  an 
abundant  vegetative  propagation.  New  branches  are  developed 
from  the  old.  "  Almost  every  living  cell  of  a  moss  can  grow  out 
into  protonema,  and  many  produce  gemmae  of  the  most  different 
kinds."  Entire  shoots  provided  with  reserve  material  are  cut 
off  and  form  new  plants.  In  this  way  moss  carpets  are  frequently 
formed  in  the  woods,  or  masses  in  bogs. 

Moss  Groups. — There  are  two  general  classes  o>f  mosses  :  ( i ) 
SPHAGNUM  forms  are  those  which  produce  leaves  without  nerves, 
and  in  which  the  sporogonium  does  not  possess  a  long  stalk  or 
seta.  What  appears  to  be  the  stalk  is  the  prolongation  of  the 
gametophyte  stem  which  is  known  as  the  pseudodiurn  or  "  false 
stalk."  These  forms  are  characteristic  of  wet  places.  Some  of 
the  group,  as  Sphagnum  proper,  form  "  sphagnum  bogs."  New 
plants  develop  on  top  of  the  old,  which  latter  gradually  die  and 
finally  pass  into  sphagnum  peat,  which  forms  thick  masses  and 
finds  use  as  a  fuel.  (2)  The  TRUE  MOSSES  are  especially  distin- 
guished by  the  differentiated  character  of  the  sporogonium,  which 
not  only  produces  a  stalk  but  also  the  peristome  (Fig.  45,  />), 
which  when  present  is  of  great  importance  in  distinguishing  the 
different  species. 

Economic  Uses  of  Bryophytes. — The  investigations  on  the 
chemistry  of  the  Liverworts  and  Mosses  have  not  been  very 
numerous.  The  constituents  which  have  been  found  are  in  the 


PRINCIPAL  GROUPS  OF  PLANTS.  85 

nature  of  tannin,  resins,  ethereal  oils,  glucosides,  alkaloids,  color- 
ing compounds,  and  organic  acids  like  citric,  oxalic,  tartaric,  and 
aconitic.  In  the  mosses  starch  and  silicon  salts  are  found  in 
addition.  Several  species  of  Marchantia  and  Jungermannia  are 


FIG.  49.  Longitudinal  sections  through  tips  of  leafy  branches  of  mosses.  A,  show- 
ing antheridia  (a,  b)  in  different  stages  of  development  and  paraphyses  or  cell-threads 
(c),  the  apical  cell  of  which  is  spherical  and  contains  chlorophyll,  and  leaves  (d,  e);  B,  show- 
ing archegonia  (a)  and  leaves  (b) ;  C,  section  of  Bryum  showing  both  archegonia,  and  an- 
theridia, paraphyses,  and  leaves;  D,  section  of  Phascum  showing  archegonia  (ar),  antheridia 
(an),  thread-like  paraphyses  (p),  and  leaves  (b). — A,  and  B,  after  Sachs;  C,  after  Limpricht; 
D,  after  Hofmeister. 

used  in  medicine.  Of  the  mosses  the  following  have  been  found 
to  have  medicinal  properties:  Sphagnum  cuspidatum,  Grimmia 
pulvinata,  Funaria  hygfometrica,  Fontinalis  antipyretica,  and  sev- 
eral species  of  Polytrichum  and  Hypnum. 


86  A  TEXT-BOOK  OF  BOTANY. 


PTERIDOPHYTES. 

The  Pteridophytes  were  formerly  known  as  the  VASCULAR 
CRYPTOGAMS.  Like  the  Bryophytes,  these  plants  show  a  distinct 
alternation  of  generations ;  i.e.,  the  gametophyte  or  sexual  genera- 
tion alternates  with  the  sporophyte  or  asexual  generation.  Their 
relation  is,  however,  somewhat  changed.  In  the  Bryophytes  the 
gametophyte  is  the  most  conspicuous  and  is  looked  upon  as  con- 
stituting the  plant  proper,  whereas  in  the  Pteridophytes  the 
gametophyte  is  rather  insignificant  in  size,  while  the  sporophyte 
constitutes  the  generation  or  phase  which  is  ordinarily  regarded 
as  the  plant.  In  the  higher  members  of  the  Pteridophytes  the 
sporophyte  is  entirely  detached  from  the  gametophyte  and  is  able 
to  lead  an  independent  existence.  This  group  also  shows  a  dis- 
tinct advance  in  structure.  There  is  a  differentiation  into  root, 
stem,  and  leaves,  and  the  development  of  a  system  of  conducting 
tissue  known  as  the  VASCULAR  SYSTEM. 

The  Pteridophytes  include  three  principal  groups,  namely,  ( I ) 
Filicales  or  Ferns,  (2)  Equisetales  or  Scouring  Rushes,  and  (3) 
Lycopodiales  or  Club  Mosses,  which  differ  considerably  in  general 
appearance  and  general  morphological  characters. 

With  the  exception  of  the  sperms  in  the  Club  Mosses,  which 
are  biciliate  and  somewhat  resemble  those  in  the  Bryophytes,  the 
sperms  in  the  Pteridophytes  are  spirally  coiled  and  multiciliate, 
and  according  to  the  number  of  cilia  of  the  sperms  some  writers 
divide  the  Pteridophytes  into  two  classes,  namely,  biciliate  and 
pluriciliate  (Figs.  51,  C;  62,  F). 

Some  of  the  Pteridophytes,  as  Selaginella  (Fig.  60),  are  dis- 
tinguished by  the  fact  that  they  produce  two  kinds  of  asexual 
spores,  which  are  known  respectively  as  MICROSPORES  (Fig.  60, 
F)  and  MEGASPORES  (Fig.  60,  E).  The  two  kinds  of  spores  are 
formed  in  separate  sporangia,  which  organs  may  occur  on  the 
same  plant  or  on  different  plants.  The  sporangia  have  the  cor- 
responding names,  microsporangia  (Fig.  60,  B,  i)  and  megaspor- 
angia  (Fig.  60,  B,g).  This  differentiation  in  sporangia  and  spores 
also  leads  to  a  differentiation  in  the  resulting  gametophytes,  the 
microspores  giving  rise  to  gametophytes  which  produce  antheridia, 
and  hence  called  male  gametophytes;  and  the  megaspores  to 


PRINCIPAL  GROUPS  OF  PLANTS.  87 

gametophytes  which  give  rise  to  archegonia,  and  hence  called 
female  gametophytes.  When  a  plant  produces  both  microspores 
and  megaspores  it  is  said  to  be  HETEROSPOROUS,  as  in  Selaginella 
(Figs.  60,  62,  and -63)  ;  while  one  that  produces  but  one  kind  of 
sporangium  and  one  kind  of  asexual  spores  is  said  to  be  ISOSPOROUS. 
In  this  connection  attention  should  be  called  to  the  fact  that  the 
spores  from  a  single  sporangium  of  an  isosporous  plant  may  give 
rise  to  male  and  female  gametophytes,  which  shows  that  a  certain 
degree  of  differentiation  in  the  spores  has  already  taken  place. 
The  causes  leading  to  the  differentiation  of  the  spores  seem  to  be 


B 


FlG.  50.  Male  fern  [Dryopteris  (Aspidium  or  Nephrodiuni)  Filix-mas],  A,  prothallus 
of  gametophyte  as  seen  from  the  under  (ventral)  side  showing  archegonia  (ar),  antheridia 
(an),  and  rhizoids  (rh) ;  B,  prothallus  showing  young  plant  (sporophyte)  which  has  devel- 
oped from  an  oospore  and  is  still  connected  with  the  gametophyte,  roots  (w),  and  the  first 
leaf  (b).— After  Schenck. 

connected  with  nutrition,  those  nuclei  which  are  in  more  favorable 
positions  giving  rise  to  larger  and  better  nourished  spores  which 
eventually  lead  to  the  formation  of  the  megaspores,  and  those 
which  are  less  favorably  placed  leading  to  the  microspores. 

The  subject  of  heterospory  is  one  of  great  interest,  and  when 
it  is  pointed  out  that  all  of  the  higher  plants  are  heterosporous 
the  subject  has  even  more  interest. 

FILICALES. 

General  Characters. — On  germination  the  asexual  spore  in 
the  Filicales  or  Ferns  gives  rise  to  a  thallus-like  body  known  as 


88 


A  TEXT-BOOK  OF  BOTANY. 


the  prothallus  which  is  frequently  dorsiventral  and  in  a  number 
of  cases  somewhat  heart-shaped,  but  varies  considerably  in  out- 
line, being  sometimes  more  or  less  tuberous.  The  prothallus  is 
frequently  but  a  few  millimeters  in  diameter,  and  the  cells  usually 
contain  chloroplasts.  On  the  under  or  ventral  surface  rhizoids 
are  usually  present  (Fig.  50,  rh).  The  sexual  organs  usually 
arise  on  the  lower  surface  (Fig.  50),  but  they  may  develop  on  the 
upper  or  dorsal  surface  or  even  laterally.  A  single  prothallus 
gives  rise  to  both  kinds  of  organs,  unless  stunted  in  its  growth, 
when  it  produces  antheridia  only. 


FIG.  51.  A,  B,  development  of  archegonia  of  a  fern  (Pteris)  showing  the  neck  (h), 
the  neck-canal  cells  (k),  and  oosphere  (e). — After  Strasburger. 

C,  development  of  antheridium  in  the  Venus-hair  fern  (Adiantum  Capillus-Veneris): 
prothallus  (p),  antheridium  (a),  sperm  (s),  sperm  mother  cell  with  starch  grains  (b); 
I,  immature  state  of  antheridium,  II,  sperms  developed,  and  III,  discharge  of  sperm  mother 
cells  and  escape  of  coiled  and  pluriciliate  sperms. — After  Sachs. 

The  antheridia  either  develop  upon  or  are  sunk  in  the  tissues 
of  the  prothallus.  The  archegonia  (Fig.  51)  are  not  flask-shaped 
as  in  the  Bryophytes.  The  venter  containing  the  oosphere  or  egg- 
cell  (Fig.  51,  e)  is  embedded  in  the  thallus,  the  structure  being 
surmounted  by  a  few-celled  neck  (Fig.  51,  h).  The  inner  cells  of 
the  neck  are  known  as  canal  cells  (Fig.  51,  k),  and  these  at  the 
time  of  ripening  of  the  egg  swell  and  exit  through  the  opening  of 
the  archegonium,  through  which  then  the  sperms  enter,  one  of 
which  unites  with  the  egg,  thus  effecting  fertilization.  The  fer- 
tilized egg  or  oospore  takes  on  a  cellulose  membrane. 


PRINCIPAL  GROUPS  OF  PLANTS. 


89 


The  oospore  which  is  held  in  the  venter  of  the  archegonium  is 
not  a  resting  spore,  but  germinates  immediately  and  early  differen- 
tiates into  the  several  organs  (Fig.  52) .  These  arise  independently 
and  include  a  stem-bud  (Fig.  52,  /)  ;  a  first  leaf  or  cotyledon 
(Fig.  52,  b),  so  called  because  it  does  not  arise  out  of  the  stem  as 
the  later  leaves  do;  a  first  or  primary  root  (Fig.  52,  w)  ;  and 
a  foot  or  haustorial  organ  (Fig.  52,  /)  whereby  it  obtains  nutri- 
ment from  the  prothallus  (Fig.  52,  pr) .  This  latter  organ  is,  how- 
ever, only  a  temporary  provision,  for  as  soon  as  the  root  grows 
out  and  penetrates  the  soil,  it  dies  off  and  the  sporophyte  thus 
becomes  independent.  The  stems  are  frequently  more  or  less  con- 


A 


FIG.  52.  The  brake  fern  (Pteris).  A,  differentiation  of  cells  in  germinating  oospores; 
B,  later  stage  showing  development  of  embryo:  pr,  prothallus;  f,  foot  embedded  in  the 
archegonium  (aw);  w,  root;  s,  young  stem;  b,  young  leaf. — A,  after  Kienitz  Gerloff;  B, 
after  Hofmeister. 

densed  and  lie  prostrate  in  the  soil,  developing  roots  from  the 
under  surface  and  leaves  from  the  sides  and  upper  surfaces.  The 
leaves  which  constitute  the  conspicuous  part  of  the  ordinary  ferns 
consist  of  a  stalk  and  lamina  or  blade  on  which  are  borne  the  spor- 
angia (Figs.  53  to  55).  The  sporangia  usually  occur  on  the 
under  surface  of  the  leaf  in  groups  or  clusters  known  as  SORI 
(Fig.  53,  A).  The  sori  are  of  characteristic  shape  and  in  certain 
species  are  covered  by  a  plate  called  the  INDUSIUM  (Fig.  53,  B) 
which  rises  from  the  epidermis.  In  some  species  the  entire  leaf 
becomes  a  spore-bearing  organ,  and  is  then  known  as  a  SPORO- 
PHYLL  (Figs.  54,  55),  to  distinguish  it  from  the  foliage  leaves. 
The  sporangia  develop  a  row  of  cells  around  the  margin  consti- 


A  TEXT-BOOK  OF  BOTANY. 


tuting  what  is  known  as  the  ANNULUS  (Fig.  53,  «).  The  form  of 
the  annulus  determines  the  manner  of  dehiscence  of  the  sporangia, 
which  occurs  on  drying.  The  spores  are  ejected  with  consider- 


FIG.  53.  Male  fern  [Dryopteris  (Aspidium  or  Nephr odium)  Filix-mas}.  A,  portion 
of  leaflet  showing  a  number  of  more  or  less  reniform  sori  near  the  mid-vein;  B,  transverse 
section  through  a  ripe  sori  showing  clusters  of  stalked  sporangia,  which  are  covered  by 
the  indusium  (i),  an  outgrowth  of  the  leaflet;  C,  a  closed  but  ripe  sporangium  showing  the 
annulus  or  ring  (n),  and  the  irregular-shaped  spores  within;  D,  showing  the  manner  of 
bpening  of  the  mature  sporangium  and  the  dispersal  of  the  spores;  E,  two  spores  much 
magnified. — After  Dodel-Port. 

able  force  (Fig.  53,  D).  They  (Fig.  53,  E;  Fig.  57)  are  either 
bilateral  or  tetrahedral  and  require  a  short  period  to  elapse  before 
they  germinate.  They  retain  their  vitality  for  a  long1  time,  except 
those  which  are  green,  i.e.,  contain  chlorophyll.  The  spores  are 


PRINCIPAL  GROUPS  OF  PLANTS.  91 

greenish  or  yellowish   in  color,  variously  sculptured,  and  vary 
from  0.025  mm.  to  0.158  mm.  in  diameter. 

Fern  Groups. — There  are  a  number  of  distinct  groups  of 


FIG.  54.  Several  Osmundas.  i,  the  royal  fern  (0.  regalis)  showing  fertile  tip  of 
branch  and  sterile  bipinnate  leaflets  below;  2,  Clayton's  fern  (O.  Claytoniana)  showing 
three  pairs  of  fertile  leaflets  in  the  middle  and  a  number  of  sterile  leaflets  above  and  below; 
3,  cinnamon  fern  (O.  cinnamomea)  showing  a  fertile  leaf  (sporophyll)  to  the  left  and  a  sterile 
leaf  (foliage  leaf)  to  the  right, 

ferns  which  vary  considerably  in  appearance.  ( I )  In  the  Tropics 
as  well  as  in  greenhouses  TREE  FERNS,  characterized  by  an  over- 
ground stem,  occur.  The  leaves  arise  at  the  summit  of  the  stem 
or  trunk  and  form  a  crown. 


92  A  TEXT-BOOK  OF  BOTANY. 

(2)  The  TRUE  FERNS  include  by  far  the  largest  number  of 
species  which  inhabit  temperate  regions.  These  vary  consider- 
ably in  size,  ranging  from  quite  diminutive  plants  5  to  12  cm.  high, 
as  the  slender  Cliff  Brake  (Pellcea  atropurpurea  and  the  variety 


FlG.  55.  Different  types  of  Perns  and  fern  allies.  I,  fertile  and  sterile  leaves  of  slender 
cliff  brake  (Pellaea  Stelleri);  2,  ebony  spleen-wort  (Asplenium  platyneuron) ;  3,  rhizome 
with  two  leaves  of  the  common  polypody  (Polypodium  vulgare) ;  4,  maiden-hair  spleen- 
wort  (Asplenium  trichomanes) ;  5,  ternate  grape-fern  (Botrychium  ternatum),  showing  the 
tripinnate  sterile  leaf  on  the  left  and  the  upright  sporophyll  on  the  right;  6,  walking  fern 
(Camptosorus  rhizophyllus)  showing  a  new  plant  developing  from  the  tip  of  one  of  the  leaves; 
7,  fertile  and  young  sterile  leaves  of  ostrich  fern  (Onoclea  Struthiopteris). 


PRINCIPAL  GROUPS  OF  PLANTS. 


93 


cristata)  and  maiden  hair  spleenwort  (Asplenium  T rich  o  mane  s) , 
to  plants  several  feet  high,  as  in  the  several  species  of  Osmunda 
(Fig.  54),  ostrich  fern  (Fig.  55),  etc.  This  group  is  chiefly 


B 


FIG.  56.  A,  transverse  section  of  stipe  of  Dryopteris  marginalis:  E,  epidermis;  H, 
hypodermis  of  collenchymatous  cells;  P,  parenchyma  containing  starch;  V,  fibrovascular 
bundle;  S,  sieve;  T,  tracheae;  N,  endodermis  surrounding  each  bundle.  B,  transverse  sec- 
tion of  stipe  of  Osmunda  Claytoniana:  H,  hypodermis  of  lignified  sclerenchymatous  fibres; 
N,  endodermis  surrounding  a  large  central  fibrovascular  bundle;  Tn,  tannin  cells. 

characterized  by  the  underground  or  prostrate  stems,  known  as 
rhizomes,  the  part  of  the  plant  that  is  seen  above  ground  being 
the  leaf. 


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A  TEXT-BOOK  OF  BOTANY. 


(3)  There  is  also  a  group  of  ferns  known  as  WATER  FERNS 
which  are  aquatic  in  habit ;  that  is,  they  live  in  marshy  places  or 
float  on  water.  As  representatives  of  this  group  may  be  men- 
tioned Marsila,  from  whose  slender  rhizome  that  is  buried  in  the 


FIG.  57.  Some  fern  spores.  A,  B,  C,  different  views  of  the  bilateral  spores  of  the 
common  polypody  (Poly podium  vulgar e),  showing  outer  wall  (ep),  middle  wall  (ex),  inner 
wall  (end)  and  line  of  dehiscence  (dl) ;  D,  a  tetrahedral  spore  of  the  royal  fern  (Osmunda 
regalis);  E,  F,  spores  of  Ceratopteris  thalictroides  seen  in  two  views. — A-D,  after  Sadebeck; 
E-F,  after  Kny. 

muddy  bottom  of  streams  arise  the  clover-like  leaves  that 
float  on  the  water  (Fig.  59)  ;  and  Salvinia  (Fig.  58),  which  is  a 
small  floating  plant  that  develops  two  kinds  of  leaves,  one  which 
float  on  the  surface  of  the  water  and  are  more  or  less  oblong,  and 


FIG.  58.  A  water  fern  (Salvinia  natans).  A,  a  plant  seen  from  side  and  showing 
floating  leaves  at  top  attached  to  the  horizontal  stem,  root-like  finely  divided  leaves  beneath, 
and  a  cluster  of  globose  sporocarps;  B,  a  view  from  above  showing  especially  the  character 
of  the  upper  leaves;  C,  young  plant  developing  from  a  megaspore  (msp). — A  and  B,  after 
Bischoff ;  C,  after  Pringsheim. 

another  which  are  filiform,  branching,  root-like,  and  submerged. 
The  water  ferns  are  further  distinguished  by  the  production  of 
megaspores  and  microspores. 

(4)   The  ADDER'S  TONGUE  FAMILY,  to  which  Ophioglossum 


PRINCIPAL  GROUPS  OF  PLANTS.  95 

and  Botrychium  belong,  develops  a  subterranean  prothallus  which 
is  destitute  of  chlorophyll.    The  prothallus  is  in  some  cases  tube- 


FIG.  59.  Marsilea  quadrifolia  (from  Bantam  Lake,  Conn.),  a  submersed  or  emersed 
aquatic  plant  belonging  to  the  Marsileaceae,  a  family  of  the  Pteridophytes.  Of  the  forty 
different  species,  only  two  or  three  are  found  in  the  United  States.  It  produces  long,  slender 
rhizomes,  which  are  buried  in  the  muddy  bottoms  of  shallow  lakes  or  streams  and  from 
which  arise  the  leaflets  which  float  on  the  surface.  The  leaves  are  on  long,  slender  petioles 
and  4-foliate,  the  leaflets  being  mostly  triangular-obovate.  In  Marsilea  quadrifolia,  a 
European  form  growing  in  Connecticut  and  Massachusetts  and  frequently  cultivated,  the 
leaves  are  nearly  glabrous,  while  in  M.  vestita,  a  form  found  in  shallow  ditches  in  the 
Southern  States,  the  leaflets  are  usually  hairy.  This  character  is  quite  marked  in  the  spor-' 
ocarps  of  the  two  plants. — After  a  photograph  by  Henry  Troth. 


96  A  TEXT-BOOK  OF  BOTANY. 

rous,  and  the  sporophyte  produces  two  kinds  of  leaves,  namely, 
foliage  leaves,  and  fertile  leaves  or  those  which  bear  the  sporangia. 
The  sporangia  occur  on  lateral  branches  of  the  sporophyll  and 
open  at  maturity  by  means  of  a  horizontal  slit. 

Ferns  Used  in  Medicine  and  as  Foods. — Many  of  the  ferns 
contain  tannin,  a  brownish  coloring  principle,  and  in  addition 
an  anthelmintic  principle.  They  may  also  contain  ethereal  oils, 
starch,  coumarin,  aconitic  acid,  and  other  principles.  A  large 
number  have  been  used  in  medicine,  of  which  the  following  may 
be  mentioned:  Dryopteris  (Aspidium  or  Nephrodium)  maryinalis 
and  D.  Filix-mas,  yielding  the  official  Aspidium.  A  number  of 
other  species  of  Aspidium,  as  well  as  species  of  Adiantum,  As- 
plenium  and  Polypodium,  are  also  used  in  various  parts  of  the 
world.  The  rhizomes  of  some  of  the  ferns  contain  considerable 
starch  and  are  used  to  some  extent  as  foods,  as  Pteris  esculenta  of 
China ;  Pteridium  aquiliana  var.  lanuginosa  of  the  Canary  Islands  ; 
Aspidium  varium  and  Asplenium  bulbosum  of  Cochin  China. 
Polypodium  vulgare  contains  a  substance  related  to  glycyrrhizin. 
Adiantum  pe datum  and  Polypodium  Phymatodes  are  said  to  con- 
tain coumarin,  the  latter  plant  being  used  in  perfumery. 

EQUISETALES. 

The  Horsetails,  or  scouring  rushes  (Equisetums),  are  peren- 
nial plants  containing  a  large  amount  of  silica  in  their  tissues. 
Like  in  the  ferns,  the  more  or  less  branching,  creeping  rhizome 
persists  from  year  to  year,  sending  out  each  year  new  shoots.  As 
in  some  of  the  ferns,  it  develops  two  distinct  kinds  of  leaf-shoots,  a 
fertile  and  a  sterile  one,  each  of  which  is  distinctly  jointed.  The 
scale-like  leaves  are  arranged  in  circles  about  the  joints  or  nodes, 
the  work  of  photosynthesis  being  carried  on  by  the  green  stems. 
The  fertile  branch  develops  at  the  apex  a  group  of  sporophylls 
known  as  a  cone  or  strobilus.  The  archesporium,  or  initial  spore- 
producing  zone,  is  unilocular.  In  Equisetum,  the  only  representa- 
tive of  the  group,  the  spores  are  spherical  and  each  is  furnished 
with  two  spiral  bands  or  elaters  which  assist  in  its  dispersal.  Some 
of  the  Equisetums  contain  aconitic  acid  and  are  used  in  medi- 
cine. Common  scouring  rush  (Equisetum  hyemale)  is  used  for 


PRINCIPAL  GROUPS  OF  PLANTS.  97 

polishing  woods,  and  Equisetum  arvense  is  used  for  scouring 
tinware. 

LYCOPODIALES. 

The  Lycopodiales,  or  Club  Mosses  (Fig.  66),-  are  perennial 
moss-like  plants,  with  more  or  less  erect  or  creeping  and  branching 
stems,  on  which  are  borne  numerous  small  simple  leaves.  The 
sporangia  arise  either  at  the  .base  of  the  upper  surface  of  the  leaves 
or  occur  in  terminal  cones.  They  have  short  stalks,  are  uni- 
locular  and  2-valved.  The  asexual  spores  are  of  one  kind  in 
Lycopodium  and  in  the  form  of  spherical  tetrahedrons,  resulting 
from  the  manner  in  which  division  has  taken  place  (see  Vol.  II). 
In  Selaginella  (Fig.  60)  two  kinds  of  asexual  spores  are  produced, 
that  is,  both  microspores  and  megaspores,  which  in  turn  give  rise 
to  male  and  female  prothalli  respectively.  The  microspore  develops 
a  male  gametophyte  (Fig.  62)  which  remains  entirely  within  the 
spore,  and  consists  of  a  few-celled  prothallus  and  a  number  of 
mother  cells  which  produce  sperms  that  eventually  escape  by  the 
breaking  of  the  wall. 

The  megaspore  frequently  begins  to  develop  the  gametophyte 
(Fig.  63)  while  still  within  the  sporangium.  The  prothallus  con- 
sists of  a  number  of  cells  and  partly  protrudes  through  the  rup- 
tured spore  wall.  On  the  upper  part  of  the  prothallus  or  nutri- 
tive layer  a  few  archegonia  are  borne.  It  should  be  stated  that 
sometimes  the  archegonia  are  developed  very  early  on  the  pro- 
thallus tissue,  but  usually  they  are  developed  after  the  spores 
have  escaped  from  the  sporangium.  After  fertilization  of  the  egg 
a  multicellular  embryo  develops  which  shows  the  following  parts 
(Fig.  61)  :  (i)  An  elongated  cell  or  row  of  cells  which  extends 
into  the  tissues  of  the  prothallus  for  the  purpose  of  obtaining 
nutriment;  (2)  a  root;  and  (3)  a  stem  bearing  at  its  tip  two 
leaves,  or  cotyledons.  One  of  the  specially  notable  characters 
of  the  plants  of  the  Selaginella  group  is,  as  we  have  seen,  the 
great  reduction  in  size  of  the  gametophyte,  which  in  the  case  of 
the  microspore  does  not  enlarge  beyond  the  wall  of  the  spore,  and 
in  the  case  of  the  megaspore  only  partly  protrudes  beyond  its  wall. 

Isoetes. — This  is  a  genus  of  aquatic  or  marsh  plants  known 
7 


98 


A  TEXT-BOOK  OF  BOTANY. 


as  quillworts.  The  plants  produce  a  number  of  filiform  roots 
which  penetrate  the  mud,  and  a  compact  tuft  of  rush-like  leaves. 
The  plants  are  heterosporous,  as  in  Selaginella.  The  sporangia 


FIG.  60.  Selaginella  helvetica.  A,  sporophyte  consisting  of  leafy  branches  giving 
rise  to  microsporangia  (i),  megasporangia  (g),  and  rhizoids  (r);  B,  longitudinal  section  of 
portion  of  branch  showing  a  megasporangium  (g)  with  3  megaspores  in  view,  a  microspor- 
angium  (i)  containing  microspores ;  C,  a  young  microsporangium  showing  free  mother  cells 
before  formation  of  tetrads;  D,  tetrahedral  division  of  spore  mother  cell;  E,  ripe  megaspore; 
F,  four  microspores  of  tetrad  separated;  G,  microsporophyll  seen  from  above  showing  ripe 
microsporangium. — After  Dodel-Port. 

are  borne  in  the  axils  of  the  leaves,  the  outer  leaves  bearing  the 
megasporangia  and  the  inner  leaves  the  microsporangia.  The 
gametophytes  consist  of  but  a  few  cells.  While  the  group  is  het- 


PRINCIPAL  GROUPS  OF  PLANTS. 


99 


erosporous  and  the  gametophytes  resemble  those  in  Selaginella,  the 
sperms  are  multiciliate  and  coiled  as  in  the  Ferns. 

Distribution  and  Uses  of  Lycopodiales. — A  number  of  the 
Lycopodiums  are  common  on  rocks,  damp  woods,  sandy  bogs, 
and  illustrations  of  several  of  these  are  shown  in  Fig.  66.  Some 
tropical  species  are  used  in  medicine ;  the  spores  of  Lycopodium 
clavatum,  on  account  of  their  fixed  oil,  are  used  as  a  dusting 
powder,  and  for  burning  in  the  production  of  flash  lights  (see 
Vol.  II).  The  Selaginellas,  of  which  there  are  several  native 
species,  are  commonly  used  for  decorative  purposes.  Some  species 


FIG.  61.  Longitudinal  section  of  young  embryo  of  a  Selaginella  before  separation 
from  the  prothallus:  et,  suspensor;  w,  root;  f,  foot;  bl,  cotyledons;  lig,  ligules  or  bud  scales. 
— After  Pfeffer. 

are,  however,  also  used  in  medicine,  and  it  is  interesting  to  note 
that  the  spores  of  one  species  (Selaginella  selaginoides)  are  used 
like  those  of  Lycopodium. 

While  the  Pteridophytes  do  not  form  a  very  conspicuous  por- 
tion of  the  flora  at  the  present  time  and  yield  but  few  products 
of  use  to  man,  it  may  be  pointed  out  that  in  former  ages  they 
formed  the  dominant  vegetation  of  the  earth.  Many  of  the 
ancestral  forms  of  this  group  attained  the  size  of  trees  and  made 
up  the  forest  vegetation  during  the  Devonian  and  Carboniferous 
Ages,  the  latter  being  sometimes  spoken  of  as  the  age  of  Pterido- 
phytes. It  is  also  called  the  Coal  Age  from  the  fact  that  the  coal 


100 


A  TEXT-BOOK  OF  BOTANY. 


measures  were  chiefly  laid  down  during  this  period.  By  some  it  is 
thought  that  the  deposits  of  coal  of  this  age  were  probably  princi- 
pally formed  from  the  remains  of  certain  marsh  plants  including 
two  extinct  groups  of  huge,  tree-like  club  mosses  (Lepidodendron 
and  Sigillaria)  and  the  Calamites,  representatives  of  the  scouring 
rushes. 

SPERMOPHYTES. 

The  Spermophytes,  or  Seed  Plants,  constitute  the  third  of  the1 
great  divisions  into  which  plants  are  divided.    The  plants  belong- 


PIG.  62.  Successive  stages  in  the  germination  of  the  microspores  of  a  Selaginella: 
p  and  w,  cells  of  the  prothallus;  s,  cells  giving  rise  to  sperms.  A,  B,  D,  views  of  spores  from 
the  side;  C,  view  from  the  back;  in  E,  the  cells  surrounding  the  sperm  mother  cell  are  dis- 
organized; F,  two  biciliate  sperms. — After  Belajeff. 

ing  to  this  division  not  only  form  the  most  conspicuous  feature  of 
the  flora  because  of  their  size  and  general  distribution,  but  also 
because  of  the  fact  that  they  produce  flowers  renders  a  large  num- 
ber of  them  especially  attractive.  The  plants  of  this  group  are  also 
of  great  importance  from  an  economic  point  of  view.  They  fur- 
nish a  large  part  of  the  food  of  man  and  other  animals,  as  well  as 
materials  for  clothing,  shelter,  fuel,  and  divers  other  purposes. 
In  this  group  of  plants  there  are  the  highest  differentiation  of  tis- 
sues and  the  most  complicated  structure.  The  one  character  which 
especially  distinguishes  them  from  the  lower  groups  of  plants 
is  that  of  the  production  of  seeds. 


PRINCIPAL  GROUPS  OF  PLANTS.  101 

The  plants  have  for  the  most  part  well-differentiated  stems 
and  leaves,  and  represent  the  sporophyte  or  asexual  generation. 
The  sporophyte  produces  sporophylls  which  are  of  two  kinds, 
namely,  megasporophylls  and  microsporophylls.  The  megasporo- 
phylls  bear  small  ellipsoidal  bodies  known  as  ovules,  which  develop 
into  seeds.  The  megasporangium  is  not  separate  and  distinct  in 
the  spermophytes  as  it  is  in  Selaginella,  but  is  embedded  within  an 
ovule  and  corresponds  to  that  part  of  the  ovule  known  as  the 
nucellus.  The  nucellus  encloses  the  embryo-sac,  which  is  regarded 
as  a  megaspore  (Figs.  70,  71,  and  81).  Each  megasporangium 
(nucellus)  therefore  contains  but  a  single  megaspore,  whereas  in 
Selaginella  the  megasporangia  contain  from  I  to  8  megaspores. 
The  microsporophyll  bears  microsporangia  (pollen  sacs)  which 
contain  microspores  (pollen  grains).  The  female  gametophyte  in 
the  Spermophytes  is  still  more  limited  in  its  development  than 
even  in  the  highest  Pteridophytes  (as  Selaginella  and  Isoetes) 
and  remains  wholly  within  the  megaspore  or  embryo-sac.  As  a 
result  of  fertilization  of  the  egg-cell  an  embryo  is  produced  which 
consists  of  root,  stem,  and  one  or  more  cotyledons  and  which  with 
the  integuments  covering  it  constitutes  the  seed. 

Spermophytes  embrace  two  well-defined  groups,  namely,  (i) 
Gymnosperms,  or  naked-seeded  plants,  and  (2)  Angiosperms,  or 
enclosed-seeded  plants. 

GYMNOSPERMS. 

In  the  Gymnosperms  the  ovules,  each  of  which  contains  a 
megasporangium  (nucellus),  are  borne  on  an  open  sporophyll 
(carpel),  and  thus  are  exposed,  as  are  also  the  seeds  developed 
from  them.  In  the  Angiosperms  the  ovules  are  borne  within 
closed  sporophylls,  and  are  thus  protected  or  covered  until  the 
seeds,  which  develop  from  them,  mature. 

The  Gymnosperms  represent  an  ancient  group  of  plants  and 
were  more  numerous  during  the  Triassic  period  than  now.  They 
are  mostly  shrubs  and  trees,  and  do  not  shed  their  leaves  period- 
ically as  the  Angiosperms  do,  and  hence  are  known  as  "  ever- 
greens." As  in  some  of  the  Pteridophytes  (Lycopodium,  Equi- 
setum),  the  sporophylls  occur  in  groups  forming  cones  or  strobiles 
(Fig.  72).  They  not  only  differ  in  external  appearance  from  the 


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A  TEXT-BOOK  OF  BOTANY. 


Angiosperms  but  also  in  the  anatomical  structure  of  the  stem, 
which  is  without  large  conducting  vessels.  In  order  to  understand 
the  relation  of  the  Gymnosperms  to  the  Pteridophytes  on  the  one 
hand  and  to  the  Angiosperms  on  the  other,  it  will  be  necessary  to 
consider  briefly  the  life  history  of  a  representative  group,  such  as 
the  Coniferae. 

General  Characters. — The  seed  consists  essentially  of  three 
parts,  namely,  a  woody  or  leathery  seed-coat,  a  nutritive  layer 
rich  in  oil  known  as  the  endosperm,  and  a  straight  embryo.  The 
latter  is  a  more  or  less  differentiated  plantlet,  consisting  of  a  stem 


spm 


FIG.  63.  The  female  gametophyte  of  a  Selaginella;  prothallus  (pr)  projecting  through 
the  ruptured  wall  (spm)  of  the  megaspore;  ar,  sterile  archegonium;  embi,  emb2,  two  embryos 
embedded  in  the  tissue  of  the  prothallus;  et,  et,  suspensors. — After  Pfeffer. 

with  a  varying  number  of  cotyledons  or  first  leaves  (2  to  16), 
and  a  small  root  which  is  attached  to  a  suspensor,  as  is  the  embryo 
in  Selaginella  (Fig.  63).  When  the  embryo  begins  its  develop- 
ment into  the  plant  it  uses  up  the  nourishment  with  which  it  is 
surrounded  in  the  endosperm,  and  as  it  increases  in  size  the  seed- 
coat  is  split.  The  root  then  protrudes  and  the  cotyledons,  to  some 
of  which  the  seed-coat  is  still  attached,  are  carried  upward  by  the 
stem  through  the  surface  of  the  soil,  when  the  seed-coat  is  cast 
off  and  the  plant  begins  an  independent  existence.  The  first  root 
is  the  primary  or  tap  root,  and  from  this  are  sent  out  numerous 
branches  known  as  secondary  roots,  constituting  a  well-developed 


PRINCIPAL  GROUPS  OF  PLANTS.  103 

root  system  which  serves  the  double  purpose  of  absorbing  nutri- 
ment from  the  substratum  or  soil  and  holding  or  fixing  the  plant 
in  its  upright  position.  The  embryonal  stem  grows  vertically 
upwards,  continuing  its  growth  indefinitely.  Lateral  branches 
arise  at  more  or  less  regular  intervals  which  extend  from  near  the 
ground  to  the  apex,  the  younger  branches  continually  succeeding 


FIG.  64.  Bjrd's  Nest  Moss  (Selaginella  lepidophylla) .  A,  the  plant  growing  in  a 
moist  situation  or  upon  the  addition  of  water;  B,  the  habit  of  the  plant  under  dry  conditions, 
it  unrolling  and  becoming  as  (A)  upon  the  addition  of  water.  This  plant  is  also  known 
as  Resurrection  plant  and  Rose  of  Jericho,  the  latter  name  is  more  correctly  applied  to 
Anastatica  hierochuntica,  a  cruciferous  plant  of  the  East  Mediterranean  and  Egypt,  the 
stems  on  drying  becoming  folded  together  and  the  whole  plant  being  scattered  by  the  wind. 
The  Bird's  Nest  Moss  grows  in  Mexico  and  western  Texas,  and  in  the  rolled-up  condition 
(B)  is  found  occasionally  in  commerce  and  is  used  as  a  table  decoration.  It  has  the  advan- 
tage that  even  though  it  dries  out,  it  may  be  renewed  many  times. — After  Hieronymus 
in  Engler  and  Prantl. 

the  older  ones  from  the  ground  upward,  thus  giving  the  trees 
a  cone-like  outline.  The  leaves  arise  on  the  branches  and  are  of 
two  kinds,  primary  leaves  which  are  more  or  less  scale-like  and 
deciduous,  and  secondary  leaves  which  are  true  foliage  leaves, 
and  are  usually  quite  simple  in  structure.  The  leaves  vary  in 
form  but  are  usually  narrow  and  somewhat  thickened,  giving 
them  a  needle-like  appearance. 


104  A  TEXT-BOOK  OF  BOTANY. 

In  addition,  sporophylls  (spore-bearing  leaves)  are  formed  at 
the  ends  of  the  young  shoots  or  in  the  axils  of  more  mature  ones 


FlG.  65.     A  piece  of  slate  from  the  coal  formation  in  Shenandoah,  Pennsylvania,  showing 
a  fossil  fern  which  is  probably  a  species  of  Neuropteris. 

(Fig.  69).  These  are  compactly  arranged,  forming  cones  or  stro- 
bili  which  are  always  of  two  kinds  and  borne  on  different  twigs 
of  the  same  plant  or  on  different  plants.  The  staminate  cones 


PRINCIPAL  GROUPS  OF  PLANTS.  105 

consisting  of  microsporophylls  (stamens)  are  more  or  less  elon- 
gated and  cylindrical  or  ovoid  (Fig.  69,  A).  The  carpellate 
cones  consisting  of  megasporophylls  (carpels)  have  a  shorter 
longitudinal  axis,  and  the  cones  vary  considerably  in  the  different 
groups  (Fig.  72). 


FlG.  66.  Several  species  of  Lycopodium.  i,  Ground  pine  (L.  ohscuruni)  showing  a 
leafy  branch  with  one  strobile  at  the  apex;  2,  a  branch  of  trailing  Christmas  green  (L. 
complanatum)  bearing  four  or  five  strobiles  at  the  apex  of  long  dichotomously  branching 
stalks;  3,  club  moss  or  running  pine  (L.  clavatum)  with  a  branch  bearing  four  strobiles; 
4,  shining  club  moss  (L.  lucidulum)  with  small  sporangia  borne  in  the  axils  of  the  leaves. 

The  Microsporophylls  (Fig.  69)  are  usually  of  a  yellowish- 
brown  color,  and  consist  of  a  slender  stalk  and  a  lamina  which 
bears  the  microsporangia  (pollen  sacs)  on  the  lower  or  dorsal 
surface  (Fig.  69,  B,  C).  In  this  they  show  a  resemblance  to 


io6 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  67.     White  Pine,  also  called  Weymouth  Pine,  (Pinus  Strobus).— From  a  photograph 
by  Mr.  C.  J.  Hibbard  in  "  Minnesota  Trees  and  Shrubs." 


PRINCIPAL  GROUPS  OF  PLANTS. 


107 


ferns  where  the  sori  are  borne  on  the  under  surface  of  the  leaves. 
The  microsporangia  vary  in  number  from  2  to  15,  and  are  pro- 
tected in  various  ways,  either  being  sunk  in  the  tissues  of  the  sporo- 
jphyll,  as  in  Pinus  and  Abies,  or  they  are,  as  in  Juniperus  and 
\Thuja,  provided  with  a  covering  resembling  the  indusium  of  the 
isori  of  the  ferns.  The  walls  are  variously  thickened  and  on  drying, 


>}f%2f 


Dan 


S.W 


s.w 


FIG.  68.  Pinus  reftexa.  Transverse  section  of  a  portion  from  the  inner  face  of  the 
spring  wood  showing  a  schizogenous  resin  duct  or  passage  with  the  central  canal  (C)  and 
the  thin-walled  and  resinous  epithelium  (ep);  with  parenchyma  tracheids  (t),  the  spring 
wood  (Sp.  W.)  and  the  summer  wood  (S.  W.). — After  Penhallow. 

The  Coniferae  represent  the  most  ancient  group  in  which  resin  passages  or  reservoirs 
are  found.  While  these  passages  show  certain  important  variations  in  structure  and  origin, 
and  while  even  in  certain  genera  of  the  group,  as  in  the  genus  Pinus,  they  exhibit  consider- 
able variation  in  detail,  yet  in  this  genus  they  are  all  of  the  same  structural  type  as  in  Pinus 
reflexa,  the  white  pine  of  the  high  mountainous  regions  of  New  Mexico  and  Arizona.  The 
epithelial  tissues  are  thin-walled  and  readily  broken  in  making  sections  except  in  the  hard 
pines  as  the  Loblolly  pine  (P.  Tceda),  where  ths  cells  often  become  strongly  resinous.  (See 
Penhallow's  "Manual  of  the  North  American  Gymnospenns.") 

owing  to  unequal  tension,  the  sacs  are  ruptured  longitudinally 
and  the  spores  scattered.  The  microspores  are  very  numerous, 
sometimes  forming  powdery  deposits.  They  are  either  i -celled 
or  3-celled.  In  the  latter  case  two  lateral  cells  act  as  wings  for 
the  dispersal  of  the  spores  by  the  wind  (Fig.  69,  D). 


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A  TEXT-BOOK  OF  BOTANY. 


The  Megasporophylls  consist  of  sessile  carpels  (leaves)  on 
which  are  borne  one  or  two  naked  ovules  containing  the  sporangia 
(nuclei).  In  certain  groups,  as  in  the  pines,  balsams,  etc.,  a 
scale  is  formed  at  the  base  of  the  carpel  which  bears  the  ovules, 
and  this  scale  is  called  the  seminiferous  scale.  The  ovules  con- 
sist of  several  parts  (Figs.  70  and  71)  :  a  stalk;  an  integument  or 
wall  which  has  an  opening  at  the  apex  known  as  the  micropyle ; 
a  nucellus  (megasporangium),  being  that  portion  next  within  the 


FIG.  69.  A,  longitudinal  section  of  cone  composed  of  microsporophylls,  of  one  of  the 
pines;  B,  longitudinal  section  of  microsporophyll  showing  microsporangium  (pollen  sac); 
C,  the  same  in  transverse  section  showing  both  microsporangia;  D,  winged  microspore 
(pollen  grain),  with  a  two-celled  male  gametophyte,  the  upper  cell  being  the  generative 
cell,  the  remaining  nucleated  cell  giving  rise  to  the  pollen  tube. — After  Schimper. 

integument;  and  embedded  within  the  nucellus  a  portion  known 
as  the  megaspore  or  embryo-sac. 

Garnet ophytes. — The  development  of  the  garnet ophytes  from 
the  asexual  spores,  namely,  the  microspore  or  pollen  grain,  and 
the  megaspore  or  embryo-sac,  is  as  follows :  The  nucleus  of  the 
megaspore  divides  repeatedly  (Fig.  71),  cell  .walls  are  formed, 
and  a  multicellular  structure  known  as  the  ENDOSPERM  is  pro- 
duced. This  structure  constitutes  the  prothallus  of  the  female 


PRINCIPAL  GROUPS  OF  PLANTS. 


109 


gametophyte  (Fig.  70,  E;  Fig.  71).  In  the  upper  portion  of  the 
prothallus  (that  is,  at  the  micropylar  end),  three  to  five  archegonia 
are  formed  (Fig.  70,  a;  Fig.  71),  which  are  separated  from  one 
another  by  cells  of  the  endosperm  or  prothallus,  which  are  rich  in 
protoplasm.  The  structure  of  the  archegonium  is  much  like  that 


n 


FIG.  70.  Longitudinal  section  of  an  ovule  of  a  spruce  (Piced):  i,  integument;  nc, 
nucellus  (megasporangium) ;  e,  embryo-sac  (megaspore)  which  has  developed  the  female 
gametophyte  consisting  of  endosperm  (e),  two  archegonia  (a),  which  show  the  neck  (c), 
and  the  egg  (n);  p,  germinating  pollen  grains  (microspores)  with  pollen  tubes  (t)  which 
have  penetrated  the  nucellus  (nc)  and  reached  the  neck  cells  of  the  archegonia. — After 
Schimper. 

of  the  preceding  group,  consisting  of  a  venter  which  contains  the 
egg,  and  a  short  neck  composed  of  4  to  8  cells. 

The  male  gametophyte  begins  to  develop  while  the  pollen  is 
still  in  the  sporangium.  At  this  stage  it  consists  of  a  generative 
cell  and  a  wall-cell,  which  constitute  the  antheridium,  the  cells  of 
the  prothallus  being  usually  suppressed  (Fig.  69,  D). 

In  addition  to  the  extreme  minuteness  of  the  gametophytes 


no 


A  TEXT-BOOK  OF  BOTANY. 


we  have  also  to  note  the  character  of  the  male  gamete  or  sperm. 
With  the  exception  of  the  Cycads  and  Ginkgo,  motile  sperms  are 


FIG.  71.  Development  of  gametophyte  and  embryo  in  one  of  the  Coniferae.  e,  em- 
bryo-sac (megaspore);  a,  archegonium ;  h,  neck  of  archegonium;  i,  integument;  p,  pollen- 
tube;  n,  nucellus;  f,  wing  of  seed;  g,  fibrovascular  tissue;  kz,  canal  cells  of  archegonium; 
ka,  beginning  of  embryo;  k,  nuclei;  ws.tip  of  root;  wh,  root-cap;  c,  cotyledons;  v,  point  of 
growth  of  stem;  s,  suspensor. 

I,  early  stages  of  embryo-sac  (e);  II,  young  archegonium  (a)  after  development  of 
neck  cells  (h),  cell  lumen  (1);  III,  section  of  ovule  with  portion  of  attached  seminiferous 
scale  (f)  showing  entrance  of  pollen  tube;  IV,  embryo-sac  with  two  developed  archegonia; 
V,  archegonium  after  fertilization,  there  being  four  nuclei  at  the  lower  part,  only  two  of 
which  are  seen;  VI,  further  development  of  embryo;  VII,  VIII,  IX,  X,  showing  develop- 
ment of  large  tortuous  suspensor,  to  which  is  attached  the  young  embryo  (ka);  XI,  XII, 
mature  embryo. — After  Strasburger. 


PRINCIPAL  GROUPS  OF  PLANTS.  in 

not  found  in  the  Gymnosperms,  but  these  are  represented  by  two 
male  nuclei  which  are  transferred  directly  to  the  archegonium 
from  the  male  gametophyte,  formed  through  germination  of  the 
microspore  (pollen  grain).  It  may  be  recalled  that  in  the  Pteri- 
dophytes  the  motile  sperms  are  discharged  from  the  antheridium 
and  carried  by  the  agency  of  water  to  the  archegonium,  but  in  the 
Gymnosperms  water  is  no  longer  a  medium  of  transferral.  The 
microspores  themselves  are  carried  to  the  ovules  usually  through 
the  agency  of  wind,  after  which  they  germinate,  developing  a  tube 
which  carries  the  male  nuclei  directly  to  the  archegonium  without 
their  ever  having  been  free. 

The  transferral  of  the  microspores  or  pollen  grains  to  the 
ovule  is  known  as  pollination.  After  pollination  the  wall-cell  de- 
velops a  tube,  the  pollen  tube,  and  the  generative  cell  gives  rise 
to  two  male  nuclei,  which,  with  the  remaining  protoplasmic  con- 
tents of  the  antheridium,  are  carried  by  the  pollen  tube  to  the 
micropyle,  which  it  enters,  penetrating  the  tissue  of  the  nucellus 
(Fig.  70,  t).  On  reaching  the  neck  of  an  archegonium  the  pollen 
tube  pushes  its  way  down  into  the  venter,  where  it  discharges 
one  of  the  sperm  nuclei,  which  unites  with  the  egg,  forming  an 
oospore.  Cessation  in  growth  does  not  yet  take  place  and  the 
oospore  develops  into  the  embryo  already  described.  The  develop- 
ing embryo  obtains  its  nourishment  by  means  of  a  suspensor 
(Fig.  71,  s),  which  also  places  the  embryo  in  a  favorable  position. 

There  being  several  archegonia  in  an  ovule  (Figs.  70,  71),  a 
corresponding  number  of  embryos  may  be  formed,  but  rarely 
more  than  one  survives.  While  the  embryo  is  developing,  the 
other  tissues  of  the  megaspore  are  likewise  undergoing  changes 
leading  to  the  maturity  of  the  seed.  The  carpels  and  seminifer- 
ous scales  also  continue  to  grow,  and  they  usually  become  more  or 
less  woody,  forming  the  characteristic  cones  of  the  pines  (Fig. 
72),  but  may  coalesce  and  become  fleshy,  producing  the  berry-like 
fruits  of  Juniper  (Fig.  75).  The  seed  on  germination  gives  rise 
to  the  sporophyte  (tree). 

Groups  of  Gymnosperms. — There  are  several  important 
groups  of  Gymnosperms:  (i)  The  Cycads  or  Fern  Palms, 
which  are  characteristic  of  tropical  and  sub-tropical  countries. 
The  trunk  does  not  branch  as  in  the  ordinary  evergreens,  and 


112 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  72.  Cones  of  some  of  the  Coniferae.  A,  branch  of  Spruce  Pine  (Pinus  echinata) 
with  two  cones;  B,  from  Pitch  Pine  (Picea  excelsa);  C,  from  Great  Sugar  Pine  (Pinus  Lam- 
bertiand);  D,  from  Black  Spruce  (Picea  mariana);  E,  from  the  California  Silver  Fir  (Abies 
magnified);  F,  from  Loblolly  or  Frankincense  Pine  (Pinus  Tceda);  G,  branch  of  Pitch  or 
Torch  Pine  (Pinus  rigida). 


PRINCIPAL  GROUPS  OF  PLANTS.  113 

the  leaves  form  a  crown  at  the  summit  of  the  stem  or  trunk. 
An  important  character  of  some  of  the  Cycads  is  the  production 
of  multiciliate  sperms,  as  in  the  ferns,  Equisetum  and  Isoetes. 
(2)  The  Ginkgonaceae  (to  which  belongs  the  Ginkgo  or  Maidenhair 
Tree,  which  is  extensively  cultivated  in  China  and  Japan  and  is 
found  wild  in  China.  It  is  very  widely  cultivated  in  this  country, 
owing  to  its  ornamental  foliage ;  the  staminate  tree  is  preferable, 
as  the  seeds  of  the  pistillate  tree  have  a  very  offensive  odor.  The 
triangular  shaped  leaves  occur  in  fascicles  and  the  seeds  are 
berry-like.  (3)  The  Coniferae  is  by  far  the  most  important  group 
and  consists  of  two  families,  the  Taxacese  and  the  Pinaceae.  To 
the  Taxaceae  belongs  Taxus,  or  yew,  a  low  tree  bearing  flat,  linear 
leaves  and  a  seed  which  is  exposed  and  surrounded  by  the  scarlet, 
fleshy,  aril-like  disk  or  scale. 

To  the  Pinacese  belong  most  of  our  important  Gymnosperms. 

Pinus  (Pine)  is  the  most  important  genus  (Figs.  67,  73,  and 
74).  It  is  characterized  by  having  needle-like  leaves  arranged 
2  to  5  in  a  fascicle.  The  cone  of  the  pine  is  usually  woody,  and 
upon  becoming  dry  splits  open  so  as  to  release  the  winged  seeds. 
Perhaps  the  most  valuable  member  of  this  genus  is  the  white  pine 
(Fig.  67)  which  is  found  throughout  the  northern  half  of  the 
United  States  east  of  the  Mississippi  River.  Its  timber  is  light 
brown  or  reddish,  soft  and  fine-grained,  but  not  very  strong. 
It  is  used  extensively  in  rough  building  construction. 

Pinus  palustris,  or  long-leaved  pine,  is  one  of  the  most  valuable 
members  of  this  group.  It  is  the  chief  source  of  the  terebinthinous 
products  of  this  country,  and  its  wood  contributes  no  small  part 
to  the  lumber  industry.  The  long-leaved  pine  is  tall,  straight,  has 
a  thin-scaled  bark  and  a  very  hard,  resinous  wood.  The  stem 
separates  near  the  summit  into  several  diverging  branches,  giving 
the  tree  a  flattened  top.  The  leaves  are  in  threes,  rarely  in  fours, 
from  10  to  15  inches  long,  and  the  cones  are  6  to  10  inches  long, 
the  scales  being  armed  with  short  recurved  spines.  Other  pines 
yielding  turpentine  are  Pinus  Tada,  loblolly  pine ;  Pinus  hetero- 
phylla,  Cuban  or  swamp  pine ;  Pinus  echinnata,  short-leaved  yellow 
pine. 

Tsuga  canadensis  (Hemlock)  is  a  common  tree  of  eastern 
North  America  (Fig.  73).  It  attains  a  large  size,  and  the  delicate 
8 


114 


A  TEXT-BOOK  OF  BOTANY. 


I!}  ar?  tat  ana 


FIG.  73.  Leaves  and  cones  of  Balsam  Fir  (Abies  balsamea),  Larch  (Larix  laricind), 
Douglas  Fir  or  Douglas  Spruce  (Pseudotsuga  taxifolia),  White  Pine  (Pinus  Strobus),  Hem. 
lock  (Tsuga  canadensis) ,  Spruce  (Picea  mariana),  and  Jack  Pine  (Pinus  Banksiana) . — From 
"Minnesota  Trees  and  .Shrubs." 


PRINCIPAL  GROUPS  OF  PLANTS. 


spray  of  its  branches  gives  it  a  delicate  beauty.  Although  its  lum- 
ber is  not  very  strong  nor  durable,  it  is  extensively  used.  The 
bark  is  also  used  to  an  enormous  extent  in  the  manufacture  of 
heavy  leather.  In  recent  years  many  tanneries  have  been  built  in 
the  hemlock  districts  so  as  to  be  near  the  supply  of  bark.  For 
the  finer  grades  of  leather  the  hemlock  bark  is  mixed  with  that  of 


"Pfltrohua 


\rar  auatnaca 


F>     u     o  u  r9 


1    monTana 


FIG.  74.  Cross-sections  of  leaves  of  six  different  species  of  Pinus,  showing  in  the 
diagrams  the  variation  in  the  shapes  of  the  cross-sections,  with  the  distribution  of  the  oil 
reservoirs,  and  beneath  each  an  enlarged  view  of  the  epidermal  layer  and  underlying  tissues. 
—From  "Minnesota  Trees  and  Shrubs." 

the  oak,  in  order  to  avoid  the  reddish  color  produced  by  the 
former.  V. 

Another  important  genus  is  Juniperus.  The  red  cedar  (/.  vir- 
giniana,  also  called  Sabina  virginiana}  or  savin  is  a  tree  producing 
valuable  fine-grained  soft  and  durable  wood  which  is  used  exten- 
sively in  making  chests,  pails,  posts,  etc.  It  is  interesting  to  note 
that  this  tree,  which  is  frequently  planted  to  form  windbreaks, 
develops  the  fungus  Gymnosporangium  in  the  form  of  cedar 
apples,  which  in  the  secidial  stage  produce  the  leaf  rust  of  apple. 


u6 


A  TEXT-BOOK  OF  BOTANY. 


The  berries  of  the  common  juniper  (/.  communis)  are  sweet  and 
fleshy  and  are  used  medicinally  as  a  diuretic  and  also  in  the 
manufacture  of  gin. 


FIG.  75.     A  branch  of  Red  Cedar  \Juniperus  virginiana)  with  numerous  berry-like  cones. 


PRINCIPAL  GROUPS  OF  PLANTS.  117 

Economic  Uses  of  the  Coniferae. — From  an  economic  point 
of  view  the  Coniferse  are  by  far  the  most  important  group  of 
plants  thus  far  considered.  In  fact,  they  may  be  ranked  first  in  the 
production  of  valuable  timber.  Of  those  yielding  timber  the 
following  species  may  be  mentioned :  White  pine  (Pinus  Strobus)  ; 
long- leaved,  yellow,  or  Georgia  pine  (Pinus  palustris  Mill)  ; 
spruce  pine  (Pinus  echinata)  ;  the  Redwood  of  Upper  California 
(Sequoia  sempervirens)  ;  pitch  pine  of  New  Mexico  (Pinus  pon- 
der osa)  ;  the  Scotch  fir,  the  common  pine  of  Europe  (Pinus  sylves- 
tris).  Some  of  the  woods  are  adapted  for  special  purposes:  as 
that  of  Pinus  Celubra  of  the  high  mountains  of  Europe  and 
Northern  Siberia,  which  is  excellent  for  wood-carving;  red  cedar 
(Juniperus  virginiana)  (Fig.  75)  used  in  the  making  "of  cigar 
boxes  and  lead  pencils;  balsam  fir  (Abies  balsamea)  used  in  the 
manufacture  of  wood  pulp. 

By  reason  of  the  oleoresinous  constituents  the  woods  of  some 
of  the  Coniferae  are  among  the  most  durable  known.  A  few 
years  ago  Jeffrey  examined  a  specimen  of  Sequoia  Penhallowii 
which  was  obtained  from  auriferous  gravels  of  the  Miocene  in 
the  Sierra  Nevada  Mountains  and  found  it  to  be  in  a  very  perfect 
state  of  preservation.  Penhallow  (loc.  cit.)  considers  this  to  be 
the  most  ancient  record  of  an  uninfiltrated  and  unaltered  wood. 
Coleman,  in  1898,  found  in  the  Pleistocene  clays  of  the  Don 
Valley  a  specimen  of  red  cedar  (Juniperus  virginiana}  which  not 
only  possessed  all  of  the  external  characteristics  of  this  species 
but  when  sawed  emitted  the  aromatic  odor  of  the  bark.  In  the 
Pleistocene  deposits  of  the  western  United  States  and  Canada 
are  found  more  or  less  unaltered  specimens  of  various  species  of 
Juniperus,  Pseudotsuga,  Picea,  and  Larix. 

Some  of  the  pines  yield  edible  seeds  which  have  been  used 
by  the  Indians  of  Western  America ;  as  the  edible  or  "  nut  pine  " 
of  California  and  New  Mexico  (Pinus  edulis)  ;  Pinus  monophylla, 
discovered  by  Colonel  Fremont  in  Northern  California;  Pinus 
Jeffreyi  of  Northern  California ;  and  Pinus  Pinea  of  Europe,  the 
seeds  of  the  latter  being  used  like  almonds  and  known  as  "  pig- 
none."  The  seeds  of  Pinus  Lambertiana  (Fig.  72,  C)  of  Califor- 
nia are  baked  before  being  used  as  a  food.  This  latter  species  is 
also  known  as  the  sugar  pine,  as  it  yields  a  manna-like  product. 


n8 


A  TEXT-BOOK  OF  BOTANY. 


A  manna  is  also  yielded  by  Cedrus  Libani  and  Larix  decidua.  The 
latter  is  known  as  "  Briancon  Manna,"  and  contains  melizitose. 
The  bark  of  some  species  furnishes  valuable  tanning  material,  as 
that  of  the  hemlock  spruce  (Tsuga  canadensis). 


Tbui 


FlG.  76.  Fruiting  twig  of  common  Juniper  (Juniperus  communis) ,  of  Red  Cedar  or 
Savin  (Juniperus  virginiana),  and  young  twig  of  White  Cedar  or  Arbor  Vitae  (Thuja  occiden- 
talis). — From  "Minnesota  Trees  and  Shrubs." 

The  Coniferse  yield  large  quantities  of  volatile  oils,  resins,  and 
allied  products  which  are  used  both  in  medicine  and  the  arts. 
A  number  of  them  yield  turpentine  (see  Vol.  II).  Larix  decidua 
of  the  Alps  and  Carpathian  mountains  yields  Venice  turpentine. 
Abies  balsamea  is  the  source  of  Canada  turpentine  or  balsam  of 


PRINCIPAL  GROUPS  OF  PLANTS. 


119 


fir;  Seudotanga  tnucronata  or  Douglass  Spruce  (Red  fir)  is  prob- 
ably the  source  of  a  balsam  resembling  Canada  turpentine  and 
which  is  known  commercially  as  Oregon  balsam.  Picea  Mariana 
or  black  spruce  yields  spruce  gum,  largely  used  in  the  manufacture 
of  chewing  gum,  and  is  also  the  source  of  spruce  beer.  Picea 
excelsa  or  Norway  spruce  yields  Burgundy  pitch.  Abies  alba, 
white  fir  or  silver  fir  yields  the  Strasburg  turpentine.  Canada 
pitch  is  the  resinous  exudation  from  the  common  hemlock 
( Tsuga  canadensis) .  Sandarac  is  yielded  by  Callitris  quadrivalvis 
found  growing  in  Northwestern  Africa.  Volatile  oils  are  yielded 
by  a  number  of  the  Coniferse,  of  which  the  following  may  be 
mentioned :  Juniperus  Sabina  yielding  oil  of  savin ;  Juniperus 
communis  yielding  oil  of  juniper,  both  of  which  are  used  in  medi- 


FIG.  77.  Microscopical  view  of  fragments  of  wood  found  in  the  coal  deposits  of  upper 
Silesia,  Prussia. — After  Link,  from  article  by  Potonie  on  the  origin  of  coal  and  petroleum 
in  Ber.  d.  d.  pharm.  Ges.,  1907,  p.  181. 

cine.  The  remains  of  Coniferae  (Picea,  etc.)  are  often  found  as 
fossils,  as  the  fossil  resin  amber,  which  is  used  in  the  arts,  and 
on  distillation  yields  a  volatile  oil  having  medicinal  properties. 

ANGIOSPERMS,  General  Characters. — They  constitute  the  most 
conspicuous  portion  of  the  flora,  embrace  the  greatest  variety  of 
forms,  and  are  the  most  highly  organized  members  of  the  plant 
kingdom.  They  vary  in  size  from  diminutive  plants  like  the 
windflower  to  the  giant  oak  which  shelters  it.  They  may  accom- 
plish their  life  work  in  a  few  months,  as  the  common  stramonium, 
or  they  may  persist  for  several  hundred  years,  as  the  trees  of  our 
primitive  forests.  They  may  inhabit  dry  desert  regions,  as  the 
Cacti  and  Chenopodiacese,  or  they  may  live  wholly  in  water,  as 
the  water  lilies.  In  short,  they  show  the  greatest  adaptability 


I2O 


A  TEXT-BOOK  OF  BOTANY. 


to  their  surroundings.  But  no  matter  how  diversified  they  may 
seem  in  form  and  structure,  they  agree  in  this  with  possibly  one 
exception,  namely,  mignonette,  that  the  seeds  are  produced  in  a 
closed  carpel.  This  has  been  considered,  as  already  indicated, 
to  be  the  chief  difference  between  the  Gymnosperms  and  Angio- 
sperms. 

The  two  groups  are  further  distinguished  by  several  other 
important  characters  :  (i)  The  carpel  or  carpels  (megasporophyll) 
is  developed  into  an  organ  commonly  known  as  a  pistil  (Fig.  78). 
This  organ  consists  of  three  parts,  namely,  ovary,  style,  and 
stigma,  the  ovary  enclosing  the  ovules.  (2)  In  the  Angiosperms 
the  megaspore  (embryo-sac)  develops  a  gametophyte  which  does 


FIG.  78.  A,  longitudinal  section  through  orange  flower  (Citrus  Aurantium)  showing 
stalk  (PE) ;  sepals  (s) ;  petals  (p) ;  stamen  with  filament  (F)  and  anther  (A) ;  compound 
pistil  (composed  of  united  carpels)  with  stigma  (T),  style  (Y)  and  superior  ovary  (O)  with 
ovules;  disk  or  nectary  (D).  B,  longitudinal  section  of  a  bud  of  clove  (Caryophyllus) 
showing  inferior  ovary  (0),  style  (Y),  stamens  (F),  petals  (P),  sepals  (S),  nectary  (D). 

not  give  rise  to  archegonia,  but  the  egg  arises  directly  from  the 
megaspore  nucleus  by  a  series  of  divisions.  (3)  The  Micro- 
sporophyll  (stamen)  differs  considerably  in  structure  and  appear- 
ance from  that  of  the  Gymnosperms.  The  stamen  may  be  denned 
as  a  leaf  which  bears  sporangia  (spore  cases).  It  usually  con- 
sists of  the  following  differential  parts :  filament  and  anther,  the 
latter  consisting  of  pollen  sacs  (microsporangia)  in  which  the 
pollen  grains  (microspores)  are  developed  (Figs.  78,  79,  and  80). 
(4)  In  a  large  number  of  cases  in  the  Angiosperms  there  is 
developed  in  addition  to  the  sporophylls  or  sporangial  leaves 
(stamens  and  pistils)  another  series  of  leaves  known  as  floral 
leaves  (Fig.  78).  The  latter  usually  are  of  two  kinds,  known  as 
sepals  and  petals. 


PRINCIPAL  GROUPS  OF  PLANTS.  121 

The  Development  of  the  Two  Generations,  namely,  the 
sporophyte  and  gametophyte,  is  much  the  same  in  the  Angio- 
sperms  as  in  the  Gymnosperms;  that  is,  the  sporophyte  consti- 
tutes the  plant  body  and  what  is  commonly  considered  to  be  the 
plant.  The  gametophytes  are  still  more  reduced  than  was  the 
case  in  the  Gymnosperms,  the  male  gametophyte  consisting  of 
but  two  cells. 

Beginning  with  the  germination  of  the  seed,  we  may  outline 
the  life  history  of  the  plant  as  was  done  under  Gymnosperms. 
The  seeds  in  the  two  groups  are  much  alike,  with  the  exception 
that  in  the  Angiosperms  they  usually  have  two  integuments. 
Within  the  Angiosperms  two  classes  of  embryos  are  distinguished, 
which  give  rise  to  the  most  important  division  of  this  group  of 
plants.  In  the  one  case  a  single  cotyledon  is  formed  at  the  apex 
of  the  stem,  and  all  plants  having  an  embryo  of  this  kind  are 
known  as  MONOCOTYLEDONS,  that  is,  plants  having  one  seed  leaf. 
In  the  other  case  two  cotyledons  arise  laterally  on  the  stem  and 
opposite  each  other,  and  those  plants  having  an  embryo  of  this 
type  are  grouped  together  as  DICOTYLEDONS,  or  plants  having  two 
seed  leaves.  In  the  monocotyledons  the  cotyledon  is  limited  to  one, 
but  in  the  dicotyledons  the  seed  leaves  are  not  limited  in  number 
and  there  may  sometimes  be  three  or  more. 

The  sporophyte  which  develops  from  the  germinating  seed 
consists  of  the  essential  parts  already  given,  i.e.,  root,  stem,  and 
leaves.  The  leaves  are  of  four  kinds:  (i)  Foliage  leaves,  (2) 
scale  leaves  or  bud  scales,  (3)  floral  leaves,  which  in  some  cases 
are  wanting,  and  (4)  sporangial  leaves  or  sporophylls.  Inasmuch 
as  the  latter  give  rise  to  the  gametophytes  (male  and  female)  the 
development  of  the  sporangia  in  each  will  be  considered  in  detail. 

The  Microsporangia  (pollen  sacs)  arise  by  the  division  of 
certain  cells  under  the  epidermis  of  the  anther  (Fig.  79).  This 
process  of  division  continues  until  four  regions  of  fertile  tissue 
(sporangia)  are  produced  (Fig.  79,  D).  The  sporangia  are 
directly  surrounded  by  a  continuous  layer  of  cells  which  consti- 
tutes the  tapetum  or  tapetal  cells  (Fig.  79,  f),  these  being  in  the 
nature  of  secretion  cells  and  containing  considerable  oil.  The 
tapetum  is  in  turn  surrounded  by  a  layer  of  cells  which  are 
peculiarly  thickened  and  which  on  drying  assist  in  the  opening 


122 


A  TEXT-BOOK  OF  BOTANY. 


of  the  anther  and  the  discharge  of  the  pollen,  and  this  layer  is 
called  the  endothecium  (Fig.  79,  end).  There  is  still  a  third  or 
external  layer  of  cells,  which  constitutes  the  exothecium  (Fig.  79, 
ex).  These  four  sporangial  regions  may  remain  more  or  less 
distinct  and  separate  at  maturity,  or  the  two  on  either  side  may 


c. 


fid 


FIG.  79.  Development  of  pollen  sacs  (microsporangia)  in  several  of  the  Angiosperms: 
A,  showing  beginning  of  archesporium  (a),  an  outer  sterile  layer  (b),  position  of  connective 
(con);  B,  later  stage  showing  development  of  fibrovascular  tissue  (gf);  C,  longitudinal 
section  of  archesporium;  D,  E,  F,  successive  later  stages  showing  in  addition  pollen  mother 
cells  (sm)  and  tapetum  layer  (t).  G,  H,  diagrammatic  sections  of  mature  pollen  sacs  show- 
ing pollen  mother  cells  (pm) ,  tapetum  (t) ,  endothecium  (end) ,  exothecium  (ex) ,  and  in  H 
longitudinal  dehiscence  with  formation  of  what  appears  to  be  a  unilocular  pollen  sac  on 
either  side  of  the  connective. — A-F,  after  Warming;  G-H,  after  Baillon  and  Luerssen. 

coalesce.  This  latter  usually  occurs  at  maturity,  when  dehiscence 
takes  place,  forming  apparently  a  single  pollen  sac  on  either  side 
of  the  connective  or  axis  (Fig.  79,  H). 

The  Microspores  (pollen  grains)  are  developed  somewhat 
differently  in  Monocotyledons  and  Dicotyledons.  In  most  mono- 


PRINCIPAL  GROUPS  OF  PLANTS. 


123 


cotyledons  the  nucleus  of  each  cell  (pollen  mother  cell)  making 
up  the  archesporium  divides  into  two  nuclei,  each  of  which  takes 
on  a  wall  of  cellulose.  Each  of  these  (daughter  cells)  in  turn 
divides,  giving  rise  to  four  pollen  grains.  In  dicotyledons  (Fig. 
80)  the  nucleus  of  a  mother  cell  divides  into  four  nuclei  before 
the  walls  are  formed  which  separate  the  nuclei,  thus  giving  rise 
to  the  tetrad  group  of  spores  to  which  attention  has  already  been 
called  (Fig.  60,  D)  under  Bryophytes.  The  wall  of  each  spore  is 
divided  into  two  layers,  an  inner  layer  consisting  of  cellulose 
known  as  the  intine,  which  gives  rise  to  the  pollen  tube  on  germi- 
nation of  the  spore;  and  an  outer  layer  somewhat  different  in 


FIG.  80.  Development  of  pollen  grains  (microspores)  of  garlic  (Allium  narcissi florum): 
a.,  pollen  mother  cell  with  nucleus;  b,  the  same  with  homogeneous  nucleus  and  a  thicker 
wall;  c-e,  changes  in  nucleus  prior  to  division;  f,  formation  of  spindle  with  nuclear  masses 
in  the  center  from  which  nuclear  threads  extend  to  the  poles  of  the  spindle;  g,  division  of 
nuclear  substance  and  receding  of  it  from  the  center  of  the  cell;  h-i,  further  stages  in  the 
organization  of  the  nuclear  substance  at  the  poles;  k,  formation  of  a  wall  between  two 
daughter  cells;  1,  beginning  of  division  of  one  daughter  cell;  m-n,  final  divisions  resulting 
in  the  formation  of  a  tetrad  (group  of  4  cells). — After  Strasburger. 

composition  and  variously  sculptured,  known  as  the  exine.  When 
the  spores  are  mature  the  original  walls  of  the  cells  of  the  arche- 
sporium dissolve  and  the  ripe  pollen  grains  are  set  free,  forming 
a  yellowish  powdery  mass  filling  the  pollen  sac.  In  some  cases 
the  spores  of  the  tetrads  hang  together,  or  even  the  whole  mass 
of  pollen  tetrads  may  be  more  or  less  agglutinated,  as  in  the 
orchids  and  milkweeds,  these  masses  being  known  as  pollinia. 
Male  Gametophyte. — Before  the  dispersal  of  the  pollen  grains 
or  microspores,  certain  changes  leading  to  the  development  of 
the  gametophyte  have  taken  place  (Fig.  81).  The  spore,  as  we 
have  seen,  is  unicellular.  This  divides  into  two  cells :  one,  which  is 
relatively  small,  known  as  the  mother  cell  of  the  antheridium 
(Fig.  81,  v),  and  another,  which,  composed  of  the  remaining 


i24  A  TEXT-BOOK  OF  BOTANY. 

nucleus  with  the  surrounding  cell-contents,  constitutes  the  tube-  or 
wall-cell  of  the  antheridium. 

Development  of  Ovule  and  Megasporangium  (nucellus). — 
The  ovule  at  first  develops  as  a  small  protuberance  on  the  inner 
surface  of  the  ovary,  after  which  it  differentiates  into  (a)  a  stalk 
or  funiculus  by  which  it  is  attached  to  the  ovary,  the  tissue  to 
which  it  is  attached  being  called  the  placenta;  and  (b)  an  upper 
portion  which  becomes  the  ovule  proper.  The  differentiation  of 
the  tissues  is  in  a  general  way  as  follows :  ( I )  The  cells  beneath 
the  epidermis  in  the  apical  portion  of  the  ovule  go  to  make  up  the 
megasporangium  (nucellus)  ;  (2)  the  peripheral  cells  from  below 
the  nucellus  give  rise  to  the  integuments ;  and  (3)  while  the  integu- 
ments are  developing  the  archesporium  or  mother  cell  of  the 


FlG.  81.  Development  of  male  gametophyte  in  an  Angiosperm.  I,  pollen  grain 
(microspore)  which  has  divided  into  the  mother  or  generative  cell  (v)  and  a  larger  tube-cell 
with  nucleus  (sk);  II,  appearance  of  pollen  on  treatment  with  osmic  acid  showing  the 
separation  of  the  generative  cell  (v)  from  the  wall  of  the  pollen  grain;  o,at  the  right  giving 
a  view  of  the  generative  cell  with  the  nucleus  embedded  in  the  hyaline  protoplasm;  III, 
showing  the  development  of  the  tube-cell  into  the  pollen  tube  which  contains  the  two  male 
cells  (nuclei)  or  gametes  formed  by  the  generative  cell. — After  Elfving. 

embryo-sac  (megaspore)  is  being  formed  within  the  nucellus  near 
the  apex. 

Female  Gametophyte. — The  archesporium  divides  into  two 
cells,  the  lower  one  of  which  repeatedly  divides,  finally  giving 
rise  to  the  embryo-sac  which  is  sunk  in  the  tissues  of  the  nucellus. 
The  nucleus  of  the  embryo-sac  divides  and  redivides  until  8  cells 
are  produced  (Figs.  82  and  83),  which  are  separated  into  the  fol- 
lowing groups:  (i)  Three  of  the  cells  form  a  group  lying  at  the 
apex,  the  lower  cell  of  the  group  being  the  egg  or  egg-cell,  the  other 
two  cells  being  known  as  synergids  or  helping  cells.  (2)  At  the 
opposite  end  of  the  sac  are  three  cells,  known  as  antipodal  cells, 
which  usually  develop  a  wall  of  cellulose  and  do  not  seem  to  have 
any  special  function.  (3)  Near  the  centre  of  the  sac  are  the  two 
remaining  nuclei,  which  unite  to  form  a  single  nucleus,  from 


PRINCIPAL  GROUPS  OF  PLANTS. 


125 


FIG.  82.  Development  of  embryo-sac  or  megaspore  in  an  Angiosperm.  la,  longi- 
tudinal section  through  a  young  ovule.  Ib,  longitudinal  section  through  a  rudimentary 
ovule  before  the  formation  of  the  integument,  showing  mother  cell  of  the  embryo-sac  (mega- 
spore)  (em)  and  primary  tapetal  cell  (t).  II,  later  stage  showing  the  two  cells  into  which 
the  mother  cell  has  divided,  the  nuclei  of  which  are  in  the  act  of  dividing.  Ill,  mother- 
cell  of  the  embryo-sac  divided  into  four  cells  (sporogenous  mass  of  cells) ;  the  lowest  of  these 
cells  (e)  displaces  the  rest  and  becomes  the  embryo-sac  in  IV.  IV,  pek,  is  the  primary 
nucleus  of  the  embryo-sac.  V,  two  daughter  cells  resulting  from  the  division  of  the  nucleus 
of  the  embryo-sac.  VI,  VII,  show  egg  apparatus  composed  of  two  synergids  (s)  and  the 
oosphere  (o),  and  antipodal  cells  (g).  VIII,  longitudinal  section  through  a  mature  ovule 
with  the  inner  integument  (ii),  the  outer  integument  (ai),  the  nucellus  (n),  the  vascular 
bundle  (gf)  entering  the  funiculus  (f),  and  secondary  nucleus  in  the  embryo-sac  (sek). — 
After  Strasburger. 


126  A  TEXT-BOOK  OF  BOTANY. 

which  after  fertilization  the  endosperm  is  derived.  The  embryo- 
sac,  as  it  is  organized  at  this  stage,  constitutes  what  is  regarded 
as  the  female  gametophyte  (Fig.  82).  The  undifrerentiated 
embryo-sac  constitutes  the  megaspore,  which  latter,  after  germina- 
tion or  differentiation  into  egg-cell  and  other  cells,  constitutes  the 
gametophyte.  It  is  thus  seen  that  in  the  female  gametophyte 
of  the  Angiosperm  archegonia  are  apparently  not  formed.  The 
gametophyte,  then,  consists  of  the  cell  group  containing  the  egg 
and  the  remaining  portion  of  the  embryo-sac,  which  latter  may 
be  compared  to  a  prothallus.  This  comparison  is  not  difficult  to 
understand  if  we  bear  in  mind  the  structure  of  the  gametophyte 
in  the  Gymnosperms,  and  particularly  if  we  recall  the  structure 
in  Selaginella  and  other  higher  Pteridophytes. 

Fertilization. — While  in  the  Gymnosperms  the  pollen  grains 
are  usually  provided  with  wings  so  as  to  bring  about  their  trans- 
ferral  to  the  carpel  by  the  agency  of  the  wind,  in  the  Angiosperms, 
on  the  other  hand,  the  grains  are  not  provided  with  wings,  but 
are  adapted  to  the  transferral  by  insects.  Pollination,  however, 
may  be  also  effected  by  the  wind,  as  is  the  case  with  many  of  our 
forest  trees.  After  the  deposition  of  the  pollen  grain  on  the  stigma, 
the  tube-cell  begins  to  form  a  tubular  process  (pollen  tube)  which 
carries  the  male  nuclei  to  the  egg-cell  (Fig.  83,  i).  It  pierces 
the  tissue  of  the  stigma  (Fig.  83,  h)  and  traverses  the  style  (Fig. 
83,  g)  until  it  reaches  the  micropyle  of  the  ovule,  which  it  enters 
(Fig.  83,  m)y  then  reaching  the  nucellus  it  penetrates  this,  enter- 
ing the  embryo-sac.  The  tip  of  the  tube  breaks  and  one  of  the 
generative  nuclei  which  has  been  carried  downward  unites  with  the 
egg,  after  which  a  wall  is  formed,  giving  rise  to  an  oospore.  The 
oospore  develops  at  once  into  the  embryo  or  plantlet  as  seen  in 
the  seed,  this  stage  being  followed  by  a  period  of  rest.  In  fact, 
the  young  plant  may  lie  dormant  in  the  seed  for  years. 

Development  of  Seed. — The  steps  in  the  development  of 
the  mature  seed  occur  in  the  following  order  (Fig.  84).  The 
oospore  divides  into  two  parts,  an  upper  portion  which  gives  rise  to 
the  embryo,  and  a  lower  portion  which  by  transverse  segmentation 
gives  rise  to  a  short  suspensor  (Fig.  84,  v}  which  practically  serves 
the  same  purpose  as  in  the  Gymnosperms  (page  HI).  The  em- 
bryonal cell  develops  the  embryo,  which  consists  of:  (l)a  root  por- 


PRINCIPAL  GROUPS  OF  PLANTS. 


127 


tion  which  is  connected  with  the  suspensor  (Fig.  84,  w)  ;  (2)  one 
or  two  cotyledons  (Fig.  84,  c)  which  are  attached  to  the  stem ;  (3) 
a  little  bud  at  the  apex  of  the  stem  which  is  known  as  the  plumule. 
While  the  embryo  is  developing,  the  nucleus  of  the  embryo- 
sac,  either  after  fusing  with  the  prothallial  cell  of  the  pollen  grain, 
or  in  the  absence  of  such  union,  begins  active  division,  forming, 


FIG.  83.  Diagrammatic  representation  of  fertilization  in  an  Angiosperm.  d,  floral  leaves; 
stamen  consisting  of  filament  (c)  and  anthers  (a,b),  one  of  which  (b)  has  dehisced,  exhibiting 
numerous  pollen  grains;  e,  nectar-secreting  bodies;  pistil  consisting  of  ovary  (f),  style  (g), 
and  stigma  (h).  On  the  latter  pollen  grains  (i)  are  germinating,  the  tube  (1)  of  one  of  them 
has  penetrated  the  tissues  of  the  stigma  and  style,  and  entered  the  foramen  (m),  or  opening 
of  the  ovule.  The  ovule  consists  of  several  parts:  raphe  (n),  outer  integument  (p),  inner 
integument  (q),  chalaza  (o),  nucellus  (s),  embryo-sac  or  megaspore  (t)  with  egg-cell  (z), 
synergids  (v),  antipodal  cells  (u),  and  the  nucleus  in  the  center  which  gives  rise  to  the 
endosperm. — After  Sachs. 

a  highly  nutritive  tissue  rich  in  starch,  oil,  or  proteins,  known  as 
the  endosperm  (see  chapter  on  Seed).  Simultaneously  with  the 
development  of  the  endosperm  the  nucellus  may  give  rise  to  a 
nutritive  layer  called  the  perisperm,  or  the  tissues  of  the  nucellus 
may  be  modified  and  form,  with  the  altered  integuments  or  coats 
of  the  ovule,  the  seed-coat. 

Inasmuch  as  the  Angiosperms  furnish  by  far  the  larger  pro- 
portion of  plants  and  plant  products  used  in  medicine,  it  is  desir- 


128 


A  TEXT-BOOK  OF  BOTANY. 


able  to  give  particular  attention  to  the  morphology  of  this  group, 
as  also  to  the  distinguishing  characters  of  a  number  of  the  impor- 
tant families. 

Economic  Importance. — As  indicating  the  great  usefulness  to 
mankind  of  the  products  obtained  from  the  Angiosperms  it  will  be 
sufficient  to  merely  mention  that  all  of  our  garden  vegetables  as 


FIG.  84.  Development  of  embryo  in  the  shepherd's  purse  (Capsella  Bursa-pastoris). 
I -VI,  various  stages  of  development:  Vb,  apex  of  the  root  seen  from  below,  i,  i,  2,  2,  the 
first  divisions  of  the  apical  cell  of  the  pro-embryo  (suspensor);  h,  h,  cells  from  which  the 
primary  root  and  root-cap  are  derived;  v,  the  pro-embryo;  c,  cotyledons;  s,  apex  of  the 
axis;  w,  root. — After  Hanstein. 

well  as  the  great  crops  of  cereals  like  wheat,  corn,  rye,  etc. ;  edible 
fruits  and  seeds ;  textile  products,  such  as  cotton,  flax,  etc. ;  medic- 
inal products ;  timbers  of  various  kinds,  as  oak,  mahogany,  walnut, 
chestnut,  cherry,  etc.,  are  furnished  by  this  great  group  of  plants. 

EVOLUTION. 

Contrary  to  a  popular  opinion,  the  idea  of  evolution  is  almost 
as  old  as  the  human  race.  From  the  time  when  man  began  to 
think  about  the  things  around  him  he  could  not  help  but  see  that 


PRINCIPAL  GROUPS  OF  PLANTS. 


129 


nothing  was  permanent,  and  he  could  not  help  but  wonder  how 
both  the  inorganic  and  the  organic  world  came  to  be  as  he  found 
them.  The  fact  is,  then,  that  for  years  the  thinking  element  of  the 
human  race  has  had  a  fairly  clear  conception  of  the  idea  of  evolu- 
tion; all  they  lacked  was  the  proof.  Nothing  is  more  decidedly 


FlG.  84A.     Hypothetical  tree  of  relationship  and  descent  of  the  leading  groups  of  plants. 

— After  Ganong. 

wrong  than  the  belief  that  Darwin  first  conceived  the  theory  of 
evolution.  His  renown  only  lies  in  the  fact  that  he  was  one  of 
the  first  to  suggest  an  explanation,  and  probably  also  because  his 
explanation  came  at  a  most  opportune  time  and  was  worked  up  in 
such  a  masterly  way. 
9 


130  A  TEXT-BOOK  OF  BOTANY. 

The  theory  of  evolution  has  as  its  basis  the  idea  that  the 
existing  species  of  plants  and  animals  are  the  descendants  of  earlier 
forms.  It  holds  that  there  is  an  unbroken  line  of  descent  from 
the  beginning  of  life  on  the  earth,  but  that  during  the  long  ages 
the  successive  descendants  gradually  changed  in  appearance  from 
their  ancestors  until  we  find  the  forms  of  the  present  day. 

Nearly  all  branches  of  biological  science  give  evidence  in 
support  of  the  theory  of  evolution.  Embryology,  for  instance,  has 
shown  that  in  its  development  the  individual  during  its  life,  begin- 
ning with  the  fertilization  of  the  egg-cell,  passes  through  a  series 
of  stages  which  are  thought  to  represent  the  same  series  of  stages 
through  which  the  whole  race  before  it  passed.  The  develop- 
ment of  the  individual  (i.e.,  ontogeny)  represents  in  a  very  brief 
space  of  time  the  evolution  of  the  race  (i.e.,  phylogeny).  In 
other  words,  "  ontogeny  epitomizes  phylogeny." 

Another  branch  of  science  which  is  bringing  forth  new  evi- 
dence is  the  branch  called  paleontology.  This  subject  has  to  do 
with  the  study  of  fossil  remains  and  with  the  time  they  existed 
on  the  earth  in  the  living  state.  It  has  been  found  that  fossils  from 
the  different  series  of  formations  that  make  up  the  earth's  outer 
crust  represent  a  regular  advancement  from  the  very  simplest  types 
to  those  which  are  most  complicated,  right  up  to  the  most  recent 
forms.  In  not  a  single  instance  has  a  highly  developed  form  been 
found  in  a  layer  of  rocks  representing  an  early  stage  in  the  earth's 
history. 

Every  scientist  of  the  present  time,  probably  without  exception, 
believes  in  the  theory  of  evolution,  but  there  is  a  great  diversity  of 
opinion  as  to  how  it  should  be  explained.  This  diversity  of 
thought,  instead  of  disproving  the  idea  of  evolution,  is  making  its 
truth  more  generally  felt.  The  problem,  then,  which  is  confront- 
ing the  scientist  is  not  to  prove  that  evolution  is  a  truth,  but  to 
explain  it;  to  show  how  new  forms  may  arise  from  old  ones, — 
that  is,  to  account  for  the  origin  of  species.  Among  the  many 
explanations  the  following  have  become  most  conspicuous: 

ENVIRONMENT. — It  was  naturally  thought  at  first  that  the 
natural  conditions  under  which  organic  life  developed  must  have 
a  certain  effect  upon  the  individual,  thereby  bringing  about  a  cer- 
tain modification  which  would  be  transmitted  in  successively 


PRINCIPAL  GROUPS  OF  PLANTS.  131 

greater  degree  to  those  progeny  living  under  the  same  conditions, 
and  so  gradually  give  rise  to  a  different  species.  This,  of  course, 
assumes  that  any  change  induced  by  environment  would  be  trans- 
mitted to  the  offspring,  to  be  retained  so  long  as  the  environment 
remained  constant,  an  assumption  which  -is  probably  not  far 
from  the  truth.  While  it  is  admitted  that  changes  in  the  environ- 
ment may  cause  direct  responses,  yet  it  is  doubtful  whether  they 
are  definite  or  permanent  enough  to  produce  new  forms.  Near 
the  end  of  the  eighteenth  century  this  explanation  was  supported 
by  Erasmus  Darwin  of  England,  St.  Hilaire  of  France,  and  Goethe 
of  Germany. 

USE  AND  DISUSE. — There  is  very  little  difference  between  this 
explanation  and  the  preceding  one.  Lamarck  proposed,  in  the 
early  part  of  the  nineteenth  century,  that  the  use  or  disuse  of 
organs  would  so  modify  them  that  the  acquired  differences  would 
be  inherited  by  the  offspring.  But,  here  again,  the  proof  depends 
upon  the  transmission  of  acquired  characters,  and  this  is  now 
almost  disproved. 

NATURAL  SELECTION. — In  1859  Darwin  published  his  "  Origin 
of  Species  by  Means  of  Natural  Selection,"  and  this  single  event 
revolutionized  science.  In  this  book  Darwin  arranged  an  enor- 
mous mass  of  facts  gained  through  many  travels,  incessant  obser- 
vation, and  prolonged  experiments.  He  built  up  an  argument  in 
such  a  convincing  way  as  to  immediately  attract  the  attention  of 
the  world,  not  only  of  scientists  but  of  laymen.  The  theory  of 
natural  selection  has  for  its  basis  the  idea  that  great  competition 
is  continually  taking  place  between  individuals  of  the  same  species 
and  between  the  individuals  of  various  species.  This  struggle  for 
existence  results  in  the  "  survival  of  the  fittest "  and  the  destruc- 
tion of  the  unfit.  The  idea  that  two  plants  or  animals  from  the 
same  parent  might  vary  slightly,  suggested  the  belief  that  the 
one  which  was  better  equipped  for  the  struggle  for  existence 
would  survive  and  so  transmit  its  desirable  characteristics  to  its 
offspring,  and  that  the  unfortunate  one  would  not  survive  and 
its  undesirable  characteristics  would  thus  be  lost  to  the  race. 

The  objections  to  the  theory  of  natural  selection  are  of  various 
kinds,  but  the  most  serious  is  probably  the  fact  that  it  is  hard  to 
conceive  how  a  very  slight  difference  in  character  can  be  of  advan- 


132  A  TEXT-BOOK  OF  BOTANY. 

tage  in  a  life  and  death  struggle.  Necessarily  when  natural  selec- 
tion first  begins  to  operate  on  two  individuals  the  differences  must 
be  only  slight  and  hardly  sufficient  to  give  one  of  them  such  a  vital 
advantage  over  the  other. 

MUTATION. — This  explanation  was  offered  in  1901  by  Hugo 
de  Vries  of  Holland.  The  word  mutation  means  a  change.  In 
this  sense  it  means  a  sudden  change  and  has  to  do  with  the  fact 
that  among  the  offspring  of  a  certain  individual  may  be  found 
one  or  more  individuals  markedly  differing  from  the  parent,  so 
much  so  as  to  be  regarded  in  a  few  instances  as  a  distinct  species. 
Moreover,  these  mutants,  as  they  are  called,  continue  to  breed 
true,  thereby  giving  rise  to  what  might  very  well  be  called  a  new 
species.  In  the  study  of  mutation  many  experiments  have  been 
conducted  by  scientists  and  breeders. 

MENDEL'S  LAW. — In  intimate  relationship  with  the  subject  of 
evolution  is  the  question  of  heredity.  In  the  middle  of  the  last 
century  there  lived  an  Austrian  monk,  Mendel  by  name,  who  ex- 
perimented with  the  cultivation  of  peas  and  other  plants  in  the 
monastery  garden.  In  his  studies  he  discovered  a  certain  law 
underlying  the  transmission  of  characters  in  reproduction.  This 
law,  which  for  many  years  lay  hidden  from  the  scientific  world, 
was  recently  brought  to  light  and  now  forms  the  basis  of  most 
of  the  recent  breeding  experiments  and  is  of  profound  value  in 
the  study  of  heredity.  In  the  simplest  case  it  is  as  follows:  If 
two  different  species,  A  and  B,  are  crossed,  the  result  is  a  hybrid 
(AB)  which  combines  certain  characters  of  both  parents.  When 
this  hybrid  propagates,  the  progeny  splits  up  into  three  sets :  one 
resembling  the  hybrid  parent  (AB)  ;  and  the  other  two  sets  re- 
sembling the  parent  forms  (A  and  B)  that  entered  into  the  hybrid. 
Mendel's  law  is  a  statement  of  the  mathematical  ratio  expressed  by 
these  three  groups  of  forms  derived  from  a  "  splitting  "  hybrid. 
This  means  that  in  a  series  of  generations  initiated  by  a  hybrid,  ap- 
proximately one-half  of  the  individuals  of  each  generation  will 
represent  the  hybrid  mixture,  one-fourth  of  the  individuals  will 
represent  one  of  the  pure  forms  that  entered  into  the  hybrid,  and 
the  remaining  fourth  will  represent  the  other  pure  form.  Of 
course,  the  I  :  2  :  i  ratio  holds  only  when  the  one  unit-character  is 
involved,  and  does  not  apply  to  the  hybrids  as  a  whole,  as  differ- 
ent characteristics  are  generally  inherited  independently  of  others. 


\ 

PRINCIPAL  GROUPS  OF  PLANTS. 


133          v- 


\ 

It  should  be  understood  that  the  use^of  hybrids  in  such  experi- 
mental work  is  simply  a  device  to  securt  easy  recognition  of  the 
contributions  of  each  parent  to  the  progen},  For  example,  if  red 
and  yellow  races  of  corn  are  crossed,  it  is  vefy  simple  to  recognize 
the  color  contribution  of  each  parent  to  the  hybrid  progeny,  when 
it  would  be  impossible  to  separate  the  contraction  of  two  yellow 
parents.  The  inference  is,  that  what  is  yv&  of  hybrids  is  true  of 
forms  produced  in  the  ordinary  way/so  that  laws  of  heredity 
obtained  from  a  study  of  hybrids/*nay  be  regarded  as  laws  of 
heredity  in  general.  S 

In  the  working  out  of  MejX^l's  law  it  has  been  observed  that, 
while  one- fourth  of  the  prog^y  are  like  one  parent,  the  remaining 
three-fourths  will  all  show  fie  characteristics  of  thet other  parent, 
although  only  one  ofVt'rc  renaming  three-fourths  wiH  breed  true. 
That  is  to  say  that  the  hybrids)  which  make  ur/half  of  the  progeny, 
look  like  one  of  the  parents,  ^ut  all  ^Jt3  not  breed  true  to  that 
parent. 

In  this  case  the  character  of  the  true  pure-strain  parent 
which  marks  the  hybrids  is  said  to  be  a  dominant  character,  while 
the  character  of  the  other  pure-strain  parent  is  said  to  be  a  recessive 
character,  because  in  the  hybrids  its  presence  can  not  be  observed 
and  can  be  discovered  only  by  breeding  the  hybrids. 

It  is  only  by  experiment  and  breeding  that  dominant  and 
recessive  characters  can  be  determined.  For  instance,  in  the 
culture  of  peas  the  character  of  being  tall  has  been  found  to  be 
dominant  over  the  character  of  being  dwarf.  This  means  that  all 
the  hybrids  will  be  tall,  although  one-fourth  of  their  progeny  will 
be  dwarf. 

Again  in  the  pea,  the  character  of  having  a  round  seed  is 
found  to  be  dominant  over  that  of  having  a  wrinkled  seed.  In 
wheat  the  character  of  being  beardless  is  dominant  over  that  of 
being  bearded,  and  again  the  character  of  being  susceptible  to 
rust  is  dominant  over  that  of  being  immune  to  rust. 

The  infinite  number  of  characters  which  complicates  the  study 
of  hybrids  and  the  fact  that  in  breeding  it  is  sometimes  the  dom- 
inant and  sometimes  the  recessive  character  which  is  the  desirable 
one  to  maintain  suggest  at  a  glance  the  breadth  and  difficulty  of 
the  problem. 


CHAPTER  II. 

CELL-CC/NTENTS  AND  FORMS  OF  CELLS. 
A  TYPICAL  livin'        «  be  said  to  consist  of  a  wall  and  a 

protoplast  (a  unit  o?  .^Lm) ,  although  it  is  often  customar 
to  refer  to  the  protopla^  alone  as  constituting  the  cell.  1  nis  ijv 
view  of  the  fact  that  the.  ADrotopiasni  which  makes  up  tlie'sub_ 
stance  of  the  protoplast  is  the  living  substance  of  the  pjg^ 
BfgjJ^s  the  protoplasm  other  substances  are  also  fr^  .^  ^e 
\  hence\in  a  general  way  the  eel  H  may  be  said^'be  composed 
of  a  wall  an&  contents  (cell-content^  Thewallj  as  wdl  ag  the 
cell-contents,  conVAsts  of  a  number  rf  substances,  and,  as  the  cell- 
contents  are  of  primary  importan:e  jn  tjle  development  of  the 
plant,  their  nature  and  conip^^Sn  will  be  considered  first. 

Cell-contents. — With  the  distinction  already  made  the  cell- 
contents  may  be  grouped  into  two  classes :  ( I )  Protoplasmic,  or 
those  in  which  the  life-processes  of  the  plant,  or  cell,  are  mani- 
fested; and  (2)  non-protoplasmic,  or  those  which  are  the  direct  or 
indirect  products  of  the  protoplast.  The  first  class  includes  the 
protoplasm  with  its  various  differentiated  parts,  and  the  second, 
the  various  carbohydrates  (starches  and  sugars),  calcium  oxalate, 
aleurone,  tannin,  oil,  and  a  number  of  other  substances. 

PROTOPLASMIC  CELL-CONTENTS. 

Protoplasm. — Protoplasm  occurs  as  a  more  or  less  semi- 
fluid, slimy,  granular,  or  foam-like  substance,  which  lies  close  to 
the  walls  of  the  cell  as  a  relatively  thin  layer  and  surrounding  a 
large  central  cavity  or  vacuole  filled  with  cell-sap,  or  it  may  be 
distributed  in  the  form  of  threads  or  bands  forming  a  kind  of  net- 
work enclosing  smaller  vacuoles.  Protoplasm  consists  of  two 
comparatively  well  differentiated  portions:  (i)  Certain  more  or 
less  distinct  bodies  which  appear  to  have  particular  functions  and 
to  which  a  great  deal  of  study  has  been  given,  as  the  nucleus  and 
plastids;  and  (2)  a  less  dense  portion  which  may  be  looked  upon 
134 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       135 

as  the  ground  substance  of  the  protoplast  and  which  is  now  com- 
monly referred  to  as  the  CYTOPLASM  (see  Frontispiece).  These 
differentiated  bodies  and  the  cytoplasm  are  intimately  associated 
and  interdependent.  The  nucleus  and  cytoplasm  are  present  in 
all  living  cells,  and  it  is  through  their  special  activities  that  cell 


FIG.  85.  Successive  stages  in  nuclear  and  cell  division,  n,  nucleolus;  c,  centre-spheres 
s,  chromosomes;  sp,  spindle  fibers;  A,  B,  C,  division  of  chromosomes,  i,  cell  with  nucleus 
containing  nucleolus  (n),  and  two  centrospheres  (c);  2,  showing  separation  of  nucleus 
into  distinct  chromosomes  (s)  and  the  centrospheres  at  either  pole  of  the  nucleus;  3,  forma- 
tion of  spindle  fibers  (sp);  4,  longitudinal  division  of  chromosomes;  5,  division  of  the  cen- 
trospheres; 6,  7,  8,  further  stages  in  the  development  of  the  daughter  nuclei ;  9,  formation 
of  cell-wall  whicn  is  completed  in  10  giving  rise  to  two  new  cells. — After  Strasburger. 


division  takes  place.  When,  in  addition,  plastids  are  present,  con- 
structive metabolism  takes  place,  whereby  complex  substances  are 
formed  from  simpler  ones. 

Besides  the  nucleus  and  plastids  other  protoplasmic  structures 
are  sometimes  found  embedded  in  the  cytoplasm.  These  are  the 
CENTROSPHERES  (Fig.  85,  c),  small  spherical  bodies  that  are 


136  A  TEXT-BOOK  OF  BOTANY. 

associated  with  the  nucleus  and  appear  to  be  concerned  in  cell 
division.  There  are,  in  fact,  quite  a  number  of  minute  bodies  in 
the  cytoplasm  which  may  be  always  present  or  only  under  certain 
conditions,  and  which  are  grouped  under  the  general  name  of 

MICROSOMES    Or   MICROSOMATA. 

Chemically  protoplasm  is  an  extremely  complex  substance,  but 
does  not  appear  to  have  a  definite  molecular  structure  of  its  own, 
being  composed  in  large  measure  of  proteins,  a  class  of  organic 
compounds  which  always  contain  nitrogen,  and  frequently  phos- 
phorus and  sulphur.  The  molecule  of  the  proteins  is  large  and 
more  or  less  unstable,  and  hence  subject  to  rapid  changes  and  a 
variety  of  combinations,  and  it  is  to  these  interactions  that  the 
vital  activities  of  the  plant  are  attributed. 

Nucleus. — The  nucleus  consists  of  ( I )  a  ground  substance 
in  which  is  embedded  (2)  a  network  composed  of  threads  con- 
taining a  granular  material  known  as  CHROMATIN,  and  (3)  gen- 
erally one  or  more  spherical  bodies  called  NUCLEOLES,  the  whole 
being  enclosed  by  (4)  a  delicate  membrane  (Fig.  85).  The  chro- 
matin  threads  are  readily  stained  by  some  of  the  aniline  dyes,  and 
are  mainly  composed  of  nucleins  (proteins)  rich  in  phosphorus, 
which  by  some  writers  are  supposed  to  be  essential  constituents  of 
the  nucleus  and  necessary  to  the  life  of  the  protoplast.  Chroma- 
tin  is  constant  in  the  nucleus,  and  prior  to  cell  division  the  threads 
become  organized  into  bodies  of  a  definite  number  and  shape 
known  as  CHROMOSOMES  (Fig.  85,  s). 

Plastids. — The  plastids  or  chromatophores  form  a  group  of 
differentiated  protoplasmic  bodies  found  in  the  cytoplasm  ( Front- 
ispiece) and  are  associated  with  it  in  the  building  up  of  complex 
organic  compounds,  as  starch,  oil,  and  proteins.  The  term  chro- 
matophore  means  color-bearer,  but  applies  also  to  those  plastids 
which  may  be  colorless  at  one  stage  and  pigmented  at  another. 
Hence  we  may  speak  of  colorless  chromatophores.  According 
to  the  position  of  the  cells  in  which  these  bodies  occur  and  the 
functions  they  perform,  they  vary  in  color — three  distinct  kinds 
being  recognized,  (i)  In  the  egg-cell  and  in  the  cells  of  roots, 
rhizomes,  and  seeds  the  plastids  are  colorless  and  are  called  LEUCO- 
PLASTIDS.  (2)  When  they  occur  in  cells  which  are  more  or  less 
exposed  to  light  and  produce  the  green  pigment  called  chloro- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       137 

phyll,  they  are  known  as  CHLOROPLASTIDS  or  chloroplasts.  (3)  In 
other  cases,  independently  of  the  position  of  the  cells  as  to  light 
or  darkness,  the  plastids  develop  a  yellowish  or  orange-colored 
principle,  which  may  be  termed  chromophyll,  and  are  known  as 
CHROMOPLASTIDS.  Chloroplastids  are  found  in  all  plants  except 
Fungi  and  non-chlorophyllous  flowering  plants,  and  chromoplas- 
tids  in  all  plants  except  Fungi.  Plastids  vary  in  form  from  more 
or  less  spherical  to  polygonal  or  irregular-shaped  bodies,  and 
they  increase  in  number  by  simple  fission.  They  suffer  decom- 
position much  more  readily  than  the  nucleus,  and  are  found  in 
dried  material  in  a  more  or  less  altered  condition. 

Leucoplastids. — The  chief  function  of  the  leucoplastids  is 
that  of  building  up  reserve  starches  or  those  stored  by  the  plant 
for  food,  and  they  may  be  best  studied  in  the  common  potato 
tuber,  rhizome  of  iris,  and  the  overground  tubers  of  Phaius  (Fig. 
2,  b).  The  reserve  starches  are  formed  by  the  leucoplastids  from 
sugar  and  other  soluble  carbohydrates. 

The  chloroplastids  occur  in  all  the  green  parts  of  plants 
(see  Frontispiece).  They  vary  from  3  to  n  /*,  in  diameter  and 
are  more  or  less  spherical  or  lenticular  in  shape,  except  in  the 
Algae,  where  they  are  large  and  in  the  shape  of  bands  or  disks 
(Figs.  8  and  9) ,  and  generally  spoken  of  as  chromatophores.  Chlo- 
Toplastids  are  found  in  greater  abundance  in  the  cells  near  the 
upper  surface  of  the  leaf  than  upon  the  under  surface,  the  pro- 
portion being  about  five  to  one.  These  grains,  upon  close  exam- 
ination, are  found  to  consist  of  (i)  a  colorless  stroma,  or  liquid, 
in  which  are  embedded  (2)  green  granules;  (3)  colorless  gran- 
ules; (4)  protein  masses;  (5)  starch  grains;  and  (6)  a  mem- 
brane which  surrounds  the  whole.  The  green  granules  are  looked 
upon  as  the  photosynthetic  bodies;  the  colorless  grains  are  sup- 
posed to  assist  in  the  storing  of  starch  or  in  the  production  of 
amylase,  the  conditions  for  these  processes  being  directly  opposite, 
i.e.,  when  photosynthesis  is  active,  starch  is  stored,  and  when 
this  process  is  not  going  on,  as  at  night,  amylase  is  produced  and 
the  starch  is  dissolved.  The  protein  grains  may  be  in  the  nature 
of  a  reserve  material  of  the  plastid  and  probably  are  also  formed 
in  connection  with  photosynthetic  products. 

While  the  protoplasm  has  been  termed  by  Huxley  "  The  phys- 


138  A  TEXT-BOOK  OF  BOTANY. 

ical  basis  of  life,"  the  chloroplastid  has  been  spoken  of  as  the 
mill  which  supplies  the  world  with  its  food,  for  it  is  by  the 
process  of  photosynthesis  that  the  energy  of  the  sun  is  converted 
into  vital  energy,  and  starch  and  other  products  formed,  which 
become  not  only  the  source  of  food  for  the  plant  itself,  but  also 
the  source  of  the  food-supply  of  the  animals  which  feed  upon 
plants.  In  other  words,  horse-power  is  derived  from  the  energy 
of  the  sun  which  is  stored  in  the  starch  grains  of  the  chloroplastids. 

Chromoplastids. — In  many  cases,  as  in  roots,  like  those  of 
carrot,  or  flowers  and  fruits,  which  are  yellowish  or  orange- 
colored,  there  is  present  a  corresponding  yellow  pigment,  and  to 
this  class  of  pigments  the  name  chromophyll  may  be  applied. 
Some  of  these  pigments,  as  the  carotin  in  carrot,  have  been  iso- 
lated in  a  crystalline  condition  (see  Frontispiece,  also  Fig.  86). 

Chromoplastids  usually  contain,  as  first  pointed  out  by  Schim- 
per  and  Meyer,  protein  substances  in  the  form  of  crystal-like 
bodies ;  starch-grains  may  also  be  present.  The  Chromoplastids 
are  very  variable  in  shape  and  in  other  ways  are  markedly  differ- 
ent from  the  chloroplastids.  They  are  more  unstable  than  the 
chloroplastids,  and  are  formed  in  underground  parts  of  the  plant, 
as  in  roots,  as  well  as  in  parts  exposed  to  the  light,  as  in  the  flower. 
Their  formation  frequently  follows  that  of  the  chloroplastids,  as 
in  the  ripening  of  certain  yellow  fruits,  such  as  apples,  oranges, 
persimmons,  etc. 

The  PLASTID  PIGMENTS  are  distinguished  from  all  other  color- 
substances  in  the  plant  by  the  fact  that  they  are  insoluble  in  water 
and  soluble  in  ether,  chloroform,  and  similar  solvents.  In  fact, 
they  are  but  little  affected  by  the  usual  chemical  reagents  under 
ordinary  conditions. 

Apart  from  the  difference  in  color,  the  yellow  pigment  (chro- 
mophyll) is  distinguished  from  the  green  (chlorophyll)  by  the 
fact  that  the  latter  is  said  to  contain  nitrogen,  and  also  by  their 
difference  in  behavior  when  examined  spectroscopically,  chloro- 
phyll giving  several  distinct  bands  in  the  yellow  and  orange  por- 
tion of  the  spectrum,  which  are  wanting  in  the  spectrum  of  the 
yellow  principle. 

CYTOLOGY,  or  the  science  of  cell  formation  and  cell  life.     Dur- 
ing recent  years  considerable  attention  has  been  given  by  botanists 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       139 


FIG.  86.  Various  forms  of  Chromoplastids:  A,  from  the  fruit  of  Bryonia  dioica;  B, 
the  fruit  of  the  European  mountain  ash  (Pyrus  aucuparia);  C,  the  petals  of  nasturtium 
(Tropceolum  majus);  D,  petals  of  Iris  pseudacorus,  E,  petals  of  Tulipa  Gesneriana;  F,  the 
root  of  carrot  (Daucus  Carota). — After  Dippel  in  "Das  Mikroskop." 


140  A  TEXT-BOOK  OF  BOTANY. 

to  the  studies  of  the  protoplasmic  structures  of  the  cell,  especially 
the  nucleus;  the  reason  for  this  being  that  all  of  the  vital  phe- 
nomena of  which  living  organisms  are  capable  have  their  origin 
in  these  substances.  The  nucleus  is  regarded  as  a  controlling 
center  of  cell  activity,  for  upon  it  all  growth  and  development  of 
the  cell  depend,  and  it  is  the  agent  for  the  transmission  of  specific 
qualities  from  one  generation  to  another.  Furthermore,  cytolo- 
gists  look  upon  the  chromatin  material  of  the  nucleus  as  being 
the  agent  for  the  transmission  of  individual  characters  to  offspring. 
The  reason  for  this  is  that  in  the  male  generative  cell  it  is  prac- 
tically only  the  nucleus  which  fuses  with  the  egg-cell,  no  other 
substances  entering  into  the  union.  The  centrosomes  are  usually 
apparent  during  the  process  of  nuclear  division  and  by  some 
are  regarded  as  the  controlling  organ  of  cell  division,  hence  they 
are  known  as  the  dynamic  centers  of  the  cell.  The  functions  of 
the  plastids  and  cytoplasms  are  largely,  if  not  entirely,  connected 
with  the  synthesis,  transportation,  and  dissociation  of  metabolic 
substances. 

NON-PROTOPLASMIC  CELL-CONTENTS. 

The  non-protoplasmic  constituents  of  plants  may  be  said  to 
differ  from  the  protoplasmic  cell-contents  in  two  important  partic- 
ulars, namely,  structure  and  function.  For  convenience  in  con- 
sidering them  here,  they  may  be  grouped  as  follows: 

(1)  Those  of  definite  form  including   (a)   those  which  are 
colloidal  or  crystalloidal,  as  starch  and  inulin;   (b)  those  which 
are  crystalline,  as  the  sugars,  alkaloids,  glucosides,  calcium  oxa- 
late ;  (c)  composite  bodies,  as  aleurone  grains,  which  are  made 
up  of  a  number  of  different  substances. 

(2)  Those  of  more  or  less  indefinite  form,  including  tannin, 
gums  and  mucilages,  fixed  and  volatile  oils,  resins,  gum-resins, 
oleo-resins,  balsams,  caoutchouc,  and  also  silica  and  calcium  car- 
bonate. 

I.    SUBSTANCES  DEFINITE  IN   FORM. 
COLLOIDAL  OR  CRYSTALLOIDAL. 

Starch  is  the  first  visible  product  of  photosynthesis,  although 
it  is  probable  that  simpler  intermediate  products  are  first  formed. 
This  substance  is  formed  in  the  chloroplastid  (see  Frontispiece) 
and  is  known  as  ASSIMILATION  STARCH.  Starch  grains  are 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       141 


FIG.  87.  Successive  stages  in  the  development  of  starch  grains,  in  Pellionia  Daveauana 
(A  to  N);  and  in  the  fruits  of  the  potato  plant,  Solatium  tuberosum  (P  to  R).  In  A,  two 
plastids  with  a  number  of  small  starch  grains;  B,  a  plastid  in  which  a  single  starch  grain  is 
differentiated;  C  to  L,  successive  stages  of  the  development  of  a  single  grain,  the  plastid 
body  being  shown  on  the  surface  (p);  M,  N,  the  development  of  several  2-compound  starch 
grains;  P  to  R,  the  development  of  additional  layers  at  right  angles  to  the  original  grain. — 
After  Dippel  in  "Das  Mikroskop." 

usually  found  in  the  interior  of  the  chloroplastid,  but  may  attain 
such  a  size  that  they  burst  through  the  boundary  wall  of  the 
plastid,  which  latter  in  the  final  stage  of  the  growth  of  the  starch 
grain  forms  a  crescent-shaped  disk  attached  to  one  end  of  the 


142 


A  TEXT-BOOK  OF  BOTANY. 


grain,  as  in  Pellionia.  Starch  is  changed  into  soluble  carbohy- 
drates by  the  aid  of  ferments  and  probably  other  substances,  and 
in  this  form  is  transported  to  those  portions  of  the  plant  requiring 
food.  The  starch  in  the  medullary  rays  and  in  other  cells  of  the 


§ 


FlG.  88.  A,  potato  starch  grains  showing  the  excentral  and  circular  point  of  origin 
of  growth,  and  lamellae;  B,  maranta  starch  grains  showing  fissured  point  of  origin  of  growth, 
and  distinct  lamellae;  C,  wheat  starch  grains  showing  indistinct  point  of  origin  of  growth, 
and  lamellae;  D,  corn  starch  grains,  which  are  more  or  less  polygonal  in  outline  and  have  a 
3-  to  5  -angled  point  of  origin  of  growth. 

wood  and  bark  of  plants  is  distinguished  by  being  in  the  form 
of  rather  small  and  nearly  spherical  grains.  In  rhizomes,  tubers, 
bulbs,  and  seeds  the  grains  are,  as  a  rule,  quite  large,  and  possess 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       143 

more  or  less  distinct  characteristics  for  the  plant  in  which  they 
are  found.  Starch  of  this  kind  is  usually  spoken  of  as  RESERVE 
STARCH  (Fig.  87). 

Occurrence  of  Starch. — Starch  is  found  in  most  of  the  algae 
and  many  of  the  mosses,  as  well  as  in  the  ferns  and  higher  plants. 
The  amount  of  starch  present  in  the  tissues  of  plants  varies. 
In  the  grains  of  rice  as  much  as  84.41  per  cent,  has  been  found. 
This  constituent  also  varies  in  amount  according  to  the  season 
of  the  year.  Rosenberg  has  observed  that  in  certain  perennial 
plants  there  is  an  increase  in  the  amount  of  starch  during  the 
winter  months,  whereas  in  other  plants  it  decreases  or  may  entirely 
disappear  during  this  period.  In  the  latter  case,  from  six  weeks 


FIG.  89.  A,  starch  grains  of  Iris  floreniina  showing  peculiar  horseshoe-like  fissure 
extending  from  point  of  origin  of  growth;  B,  irregular  starch  grains  of  calumba  root;  C, 
peculiar  beaked  starch  grains  of  ginger  rhizome;  D,  starch  grains  of  bean  showing  irregular 
longitudinal  fissures;  E,  compound  starch  grains  of  oat. 

to  two  months  in  the  spring  are  required  for  its  re-formation, 
and  about  an  equal  period  is  consumed  in  the  fall  in  effecting  its 
solution. 

Structure  and  Composition  of  Starch  Grains. — The  formula 
which  is  generally  accepted  for  starch  is  (C6H10O5)n,  this  being 
recognized  by  Pfeffer,  Tollens,  and  Mylius.  It  is  supposed  that 
the  molecule  of  starch  is  quite  complex,  it  being  composed  of  dif- 
ferent single  groups  of  C6H10O5  or  multiples  of  the  same.  While 
this  formula  may  be  accepted  in  a  general  way,  still  it  has  been 
shown  that  there  are  at  least  two  substances  which  enter  into  the 
composition  of  the  starch  grain,  and  more  recent  studies  tend 
to  show  that  it  is  in  the  nature  of  a  sphero-crystalloid,  resembling 
inulin  in  some  respects.  Starch  grains  have  an  interesting  struc- 


144 


A  TEXT-BOOK  OF  BOTANY. 


ture.  They  vary  in  shape  from  ovoid  or  spherical  to  polygonal, 
and  have  a.  more  or  less  distinct  marking  known  as  the  "  hilum," 
"  nucleus,"  or  the  POINT  OF  ORIGIN  OF  GROWTH.  The  substances 
of  which  the  grains  are  composed  are  arranged  in  concentric 
layers  or  lamellae  which  are  more  or  less  characteristic  and  which 
sometimes  become  more  distinct  on  the  application  of  certain 
reagents  (Fig.  90).  The  point  of  origin  of  growth  and  alternate 
lamellae  are  stained  by  the  use  of  gentian  violet  and  other  aniline 
dyes,  which  may  be  taken  to  indicate  that  these  layers  contain  a 
colloidal  substance  somewhat  res-embling  a  mucilage,  while  the 


FIG.  90.  Successive  stages  in  the  swelling  and  disintegration  of  starch  grains  in  the 
presence  of  water  on  the  application  of  heat  (6o°-7o°  C.),or  certain  chemicals.  Potato 
starch  i-.io;  wheat  starch  iL-22. 

alternating  layers  are  stained  with  dilute  iodine  solutions  and 
are  probably  composed  of  soluble  starch,  this  latter  corresponding 
to  the  a-amylose  of  Arthur  Meyer  or  the  granulose  described 
by  Nageli.  The  peripheral  layer  of  the  grain  appears  to  be  a 
distinct  membrane.  It  is  quite  elastic,  more  or  less  porous,  and 
takes  up  stains  readily. 

While  starch  grains  usually  occur  singly,  they  are  not  infre- 
quently found  in  groups  of  two,  three,  or  four  grains,  when  they 
are  spoken  of  as  two-,  three-,  or  four-compound.  In  some  of  the 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       145 

cereals,  as  rice  and  oat,  they  are  loo-compound  or  more.  The 
individuals  in  compound  grains  are  in  some  cases  easily  separated 
from  one  another.  This  occurs  frequently  in  microscopical  prep- 
arations, and  is  especially  noticeable  in  the  commercial  starches. 

The  various  commercial  starches  belong  to  the  class  of  reserve 
starches  and  may  be  distinguished  by  the  following  characteristics  : 

1 I )  The  shape  of  the  grain,  which  may  be  spherical,  ellipsoidal, 
ovoid,  polygonal,  or  of  some  other  characteristic  form  (Figs.  88 
and  89). 

(2)  The  size  of  the  grain,  which  varies   from   I   to  2  /*  to 
about  100  /A  in  diameter. 

(3)  The  position  of  the  point  of  origin  of  growth,  which  may 
be  central  (Fig.  88,  C,  D)  or  excentral  (Fig.  88,  A,B).    In  some 
cases  there  are  apparently  two  points  of  origin  of  growth  in  a 
single  grain,  and  it  is  then  spoken  of  as  "  half-compound,"  as  occa- 
sionally found  in  potato. 

(4)  The  shape  of  the  point  of  origin  of  growth,  which  may 
be   spherical,   as   in   potato    (Fig.   88,   A}  ;   cross-shaped,   as   in 
maranta  (Fig.  88,  B)  ;  a  three-  or  five-angled  fissure  or  cleft,  as 
in  corn  (Fig.  88,  D),  or  indistinct  or  wanting,  as  in  wheat  (Fig. 
88,  C). 

(5)  The  convergence  of  the  lamellae,  which  may  be  either 
toward  the  broad  end  of  the  grain,  as  in  maranta  (Fig.  88,  B), 
or  toward  the  narrow  end,  as  in  potato  (Fig.  88,  A).     In  most 
grains  the  lamellae  are  indistinct  or  wanting,  as  in  wheat  and  corn 
(Fig.  88,  C,D). 

(6)  Behavior  toward  dilute  iodine  solutions,  the  color  pro- 
duced varying  from  a  deep  blue  in  most  starches  to  a  red  or 
yellowish-red,  as  in  the  amylodextrin  grains  of  mace. 

(7)  The  temperature  (4S°~77°  C.)  at  which  the  "  kleister  " 
or  paste  is  formed,  and  its  consistency. 

(8)  The  appearance  as  viewed  by  polarized  light,  the  distinct- 
ness of  the  cross,  as  well  as  the  degree  of  color  produced,  varying 
considerably  as  Nichol's  prism  is  revolved  (Fig.  91). 

(9)   Behavior  toward  various  reagents,  as  chromic  acid,  cal- 
cium nitrate,  chlor-zinc-iodide,  diastase,  and  various  aniline  stains, 
showing  peculiarities  of  both  structure  and  composition  (Fig.  90). 
General  Properties  of  Starch. — If  starch  is  triturated  with 

10 


146 


A  TEXT-BOOK  OF  BOTANY. 


water  and  the  mixture  filtered,  the  filtrate  does  not  give  a  reaction 
with  iodine  solution ;  if,  on  the  other  hand,  the  starch  is  previously 
triturated  with  sand  and  then  with  water,  the  filtrate  becomes  blue 


FIG.  91.  Larger  grains  of  various  starches  as  viewed  through  the  micro polariscope 
when  mounted  in  oil:  A,  potato  (70-80  M);  B,  wheat  (30—40  M);  C,  ginger  (30-50  /«.);  D, 
galangal  (45-55  M);  E,  calumba  (40-60  M);  F,  zedoary  (50-75  M)°,  G,  maranta  (35-50  /«.)• 
H,  colchicum  (10-20  /*);  I,  corn  (20-25  /A);  J,  cassava  (20-351*  );  K,  orris  root  (30-35  M)- 

on  the  addition  of  iodine  solution.  It  appears  that  in  the  latter 
operation  the  wall  of  the  grain  is  broken  and  the  soluble  starch 
present  in  the  grain  is  liberated. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       147 

If  dry  starch  and  iodine  are  triturated  together  no  color  or, 
at  the  most,  a  faint  blue  color  is  produced;  whereas,  if  a  litt'c 
water  is  added  and  the  trituration  repeated,  a  deep  blue  color  is 
immediately  produced. 

The  blue  color  of  starch  solution  and  iodine  disappears  on  the 
application  of  heat,  but  slowly  returns  on  cooling  the  solution, 
but  not  with  the  same  degree  of  intensity,  part  of  the  iodine 
being  volatilized. 

When  starch  is  heated  with  glycerin  it  dissolves,  and  if  alco- 
hol is  added  to  the  solution,  a  granular  precipitate  is  formed  which 
is  soluble  in  water,  the  solution  giving  a  blue  reaction  with  iodine. 

When  starch  is  heated  with  an  excess  of  water  at  100°  C.  for 
even  several  weeks,  dextrinization  of  the  starch  does  not  take 
place  ;  i.e.,  the  solution  still  gives  a  blue  color  with  iodine.  If,  how- 
ever, a  mineral  acid  be  added,  it  is  quickly  dextrinized,  turning 
violet-red,  reddish,  and  yellowish  with  iodine;  finally,  maltose 
and  dextrose  are  produced,  these  giving  no  reaction  with  iodine, 
but  reducing  Fehling's  solution.  The  ferments  and  other  chemi- 
cals have  a  similar  effect  on  starch. 

When  dry  starch  is  heated  at  about  50°  C.  from  15  to  30  min- 
utes the  lamellae  and  crystalloidal  structure  become  better  defined 
and  the  polarizing  effects  produced  by  the  grains  also  become 
more  pronounced.  When  starch  is  mounted  in  a  fixed  oil,  as 
almond,  the  polarizing  effects  are  more  pronounced  than  when 
it  is  mounted  in  water,  but  the  inner  structure  is  not  usually 
apparent,  unless  the  starch  has  been  previously  heated.  (For 
literature  on  the  starch  grain  see  Kraemer,  Bot.  Gazette,  Vol. 
XXXIV,  Nov.,  1902 ;  Ibid.,  Vol.  XL,  Oct.,  1905 ;  also  Eighth  In- 
ternational Congress  of  Applied  Chemistry,  Vol.  17,  p.  31.) 

BOTANICAL  DISTRIBUTION  OF  STARCH. — This  constituent  is 
commonly  present  as  a  reserve  material  in  a  large  number  of 
plants.  The  sources  of  the  commercial  starches  are  constantly 
being  extended.  The  commercial  starches  are  chiefly  obtained 
from. one  or  more  genera  of  the  Gramineae,  Marantaceae,  Eu- 
phorbiaceae,  and  Solanaceae.  The  following  is  a  list  of  the  fami- 
lies yielding  one  or  more  economic  products  which  contain 
starch:  Cycadaceae,  Gramineae,  Araceae,  Liliaceae,  Amaryllida- 
ceae,  Iridaceae,  Musaceae,  Zingiberaceae,  Cannaceae,  Marantaceae, 


148  A  TEXT-BOOK  OF  BOTANY. 

Orchidaceae,  Piperaceae,  Fagaceae,  Aristolochiaceae,  Polygonaceae, 
Phytolaccaceae,  Nymphaeaceae,  Ranunculaceae,  Menispermaceae, 
Myristicaceae,  Lauraceae,  Papaveraceae,  Cruciferae,  Rosaceae,  Legu- 
minosse,  Geraniaceae,  Rutaceae,  Simarubaceae,  Euphorbiaceae, 
Celastraceae,  Sapindaceae,  Rhamnaceae,  Malvaceae,  Thymelaeaceae, 
Punicaceae,  Myrtaceas,  Umbelli  ferae,  Loganiaceae,  Apocynaceae, 
Convolvulaceae,  Solanaceae,  Scrophulariaceae,  Gesneraceae,  Rubia- 
ceae,  Caprifoliaceae,  Valerianaceae,  and  Cucurbitaceae. 

PERCENTAGE  OF  STARCH  IN  PLANTS. — The  amount  of  starch 
in  economic  plants,  especially  those  used  for  food,  is  very  high, 
being,  on  an  average,  much  greater  than  that  of  any  other  con- 
stituent except  water.  The  percentage  of  starch,  calculated  on 
dry  material,  in  a  number  of  foods  and  spices  is  here  given :  Bar- 
ley, 5345  to  72.90;  cardamom  seed,  18.66  to  40.53;  carrot,  0.87 
to  0.92;  chestnut,  37.31  to  47.93;  chinquapin,  44.45;  cinnamon, 
10.44  to  65.72 ;  cloves,  9.41  to  51.03  ;  cocoa  (cacao),  3.83  to  48.73  ; 
corn,  36.72  to  77.54;  ginger,  46.16  to  62.53;  lentils,  45-375  mace, 
26.77  to  56.11  ;  millet,  56.70  to  74.40;  nutmeg,  17.19  to  40.12 ;  oak 
acorns,  32.64;  oats,  42.64  to  63.50;  onion,  n.oo  to  29.39;  peas, 
50.02  to  57.59;  pepper,  28.15  to  64.92;  pimenta,  16.56  to  59.28; 
potatoes  (sweet),  8  to  78.59;  potatoes  (white),  25.00  to  75.00; 
rice,  74.80  to  84.41 ;  rye,  51.15  to  74.08;  wheat,  53.66  to  76:51. 

MANUFACTURE  OF  STARCH. — In  the  preparation  of  commer- 
cial starches  the  object  is  to  break  the  cells  and  separate  the 
starch  grains,  freeing  the  product  from  the  other  constituents  of 
the  cell  as  much  as  possible.  The  preparation  of  potato  starch 
is  exceedingly  simple,  as  all  that  is  necessary  is  to  reduce  the  tubers 
to  a  fine  pulp,  the  starch  grains  being  separated  from  the  tissues 
by  means  of  a  sieve.  The  water  containing  the  starch  is  removed 
to  tanks,  the  separation  of  the  starch  being  facilitated  by  the 
addition  of  alum  or  sulphuric  acid  which  coagulates  the  dissolved 
protein  substances.  The  starch  is  washed  and  dried  over  porous 
bricks  by  exposure  to  air.  It  is  then  thoroughly  dried  in  a  hot 
chamber,  reduced  to  a  powder,  and  sifted.  One  hundred  pounds 
of  potatoes  yield  about  15  pounds  of  dry  starch.  It  is  said  that 
diseased  tubers  produce  as  good  a  quality  of  starch  as  the  sound 
tubers. 

In  the  preparation  of  the  cereal  starches  the  gluten  interferes 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       149 

with  their  ready  separation.  The  process  is  therefore  modified 
by  either  allowing  the  cereals  to  ferment,  whereby  the  gluten 
is  rendered  soluble  and  easily  removed,  or  the  flour  is  made  into 
a  dough  which  is  kneaded  over  running  water,  whereby  the  starch 
grains  are  separated.  The  starch  is  subsequently  purified  by 
washing  and  settling.  It  is  dried  by  gentle  heat  and  assumes  the 
columnar  structure  as  seen  in  the  more  or  less  irregular  particles 
in  the  commercial  product.  One  hundred  pounds  of  wheat  yield 
from  55  to  59  pounds  of  starch,  the  fermentation  process  giving  a 
larger  amount. 

In  the  preparation  of  corn  starch,  a  weak  solution  of  sodium 
hydrate  is  usually  employed  to  facilitate  the  separation  of  the 
starch.  Sulphurous  acid  is  also  used.  One  hundred  pounds  of 
corn  yield  50  pounds  of  starch. 

Rice  starch  is  prepared  by  either  an  alkaline  process  or  by  an 
acid  process  similar  to  that  used  in  the  manufacture  of  corn 
starch,  hydrochloric  acid  being  employed  instead  of  sulphurous 
acid.  Rice  yields  a  greater  percentage  of  starch  than  any  of  the 
other  raw  materials,  100  pounds  of  the  grain  giving  70  per  cent, 
of  starch. 

Starch  is  used  as  a  food  and  for  various  other  industrial  pur- 
poses. The  principal  nutritive  starches  are  sago,  tapioca,  and 
corn.  Maranta,  or  arrowroot  starch,  is  largely  employed  in  the 
preparation  of  infant  foods.  Much  of  the  dextrin  of  commerce 
is  prepared  by  the  action  of  dilute  acids  upon  potato  starch. 
Starch  for  laundry  purposes  is  prepared  from  wheat.  Rice  starch 
is  largely  used  as  a  dusting-powder.  Cassava  starch  has  consider- 
able advantages  over  the  other  starches  in  the  making  of  nitro- 
compounds,  and  is  employed  in  the  preparation  of  smokeless 
powders. 

PYRENOIDS. — In  the  chromatophores  of  a  number  of  algae  a 
distinct  body  is  observed.  It  is  more  or  less  of  a  lenticular 
shape,  stained  a  dark  purple  on  the  addition  of  iodine,  and  is 
known  as  a  Pyrenoid.  It  is  not  definitely  known  whether  it  is 
a  true  cell  organ  having  a  function  similar  to  the  plastids  in 
manufacturing  starch  or  whether  it  is  merely  a  mass  of  complex 
reserve  substances.  It  can  be  differentiated  readily  into  two 
distinct  portions:  an  inner,  somewhat  highly  refracting  and 


ISO  A  TEXT-BOOK  OF  BOTANY. 

consisting  of  protein  matter,  and  an  outer  layer,  consisting  of  a 
number  of  starch  grains.  The  studies  of  Baubier  tend  to  show 
that  the  pyrenoid  is  perfectly  differentiated  and  independent  of 
the  chromatophore,  and  that  the  starch  is  formed  from  a  leuco- 
plastid  which  surrounds  a  phyto-globulin  or  crystalloid  at  the 
center.  This  would  quite  agree  with  the  studies  of  Timberlake, 
who  observed  the  complete  conversion  of  the  pyrenoid  into  starch. 
That  the  substances  of  the  pyrenoid  are  in  the  nature  of  reserve 
food  materials,  is  apparent  from  the  fact  that  the  pyrenoid  entirely 
disappears  in  Hydrodictyon  prior  to  spore  formation,  and  that 
it  is  afterward  formed  anew  in  the  young  cells,  thus  behaving 
very  much  like  a  leucoplastid.  Attention  should  also  be  directed 
to  the  fact  that  in  some  of  the  unicellular  and  filamentous  algse 
the  pyrenoid  divides  during  the  division  of  the  cell,  thus  behaving 
like  other  protoplasmic  organs. 

INULIN  appears  to  be  an  isomer  of  starch  and  occurs  in  solution 
in  the  cell-sap  of  parenchyma  cells  of  stems  and  roots,  being  also 
found  in  the  medullary  rays.  It  exists  in  greatest  amounts  during 
the  early  fall  and  spring,  being  changed  at  other  times  to  levulose. 
In  the  Monocotyledons  it  is  found  in  the  Amaryllidaceae,  Liliaceae, 
etc.  In  the  Dicotyledons  it  is  characteristic  of  the  Compositae, 
but  also  occurs  in  the  following:  Asclepiadaceae,  Bignoniaceae, 
Cactaceae,  Campanulacese,  Capri foliaceae,  Compositae,  Cruciferae, 
Droseraceae,  Euphorbiaceae,  Geraniaceae,  Labiatae,  Leguminosae, 
Lythraceae,  Magnoliaceae,  Menispermaceae,  Moraceae,  Nepenth- 
aceae,  Passifloraceae,  Ranunculaceae,  Rubiaceae,  Rutaceae,  Salicaceae, 
Santalaceae,  Theaceae,  Thymelaeaceae,  Urticaceae,  Valerianaceae, 
Verbenaceae,  Violaceae,  etc. 

According  to  Dragendorff,  there  are  two  forms  of  inulin ;  one 
of  which  is  amorphous  and  easily  soluble  in  water,  and  another 
which  is  crystalline  and  difficultly  soluble  in  water.  The  latter 
is  probably,  however,  a  modification  of  the  former,  and  it  is  not 
unlikely  that  the  various  principles  known  as  pseudoinulin,  inu- 
lenin,  helianthenin,  and  synantherin  are  all  modifications  of  inulin. 

In  examining  fresh  material  (Fig.  92)  the  sections  should  be 
mounted  in  as  little  water  as  is  necessary  to  enclose  the  section. 
If  inulin  is  present  it  shows  in  the  form  of  colorless,  highly 
refracting  globules.  The  latter  are  usually  relatively  small  and 
tend  to  unite,  forming  one  or  more  large  globules.  Upon  increas- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       151 

ing  the  amount  of  water  they  dissolve  and  are  diffused  among  the 
other  constituents.  If  fresh  sections  are  mounted  directly  in 
alcohol,  or  if  to  the  original  aqueous  mount  strong  alcohol  is 
added,  the  inulin  separates  in  the  form  of  rod-like  or  needle-like 
crystals,  which  strongly  polarize  light.  If  the  plant  material  is 
preserved  for  some  days  in  70  per  cent,  alcohol,  the  inulin  separates 
in  the  form  of  sphere-crystals  which  adhere  to  the  walls  of  the  cell. 
This  aggregate  consists  of  concentric  layers  of  radially  arranged, 
needle-shaped  crystals,  the  structure  of  which  is  more  apparent 
upon  the  addition  of  either  nitric  acid  or  a  solution  of  hydrated 
chloral.  The  crystal  mass  is  insoluble  in  glycerin  and  sparingly 
soluble  in  cold  water.  It  is  soluble  in  warm  water,  warm  solu- 
tions of  glycerin  and  water,  acetic  acid,  mineral  acids,  chlor- 
zinc-iodide,  and  ammoniacal  solution  of  cupric  oxide.  With  solu- 
tions of  the  alkalies  it  dissolves  with  a  lemon  yellow  color,  and 
with  acetic  acid  the  crystals  dissolve,  forming  a  greenish  colored 
solution  which  soon  fades. 

Tunmann  (Ber.  d.  d.  pharm.  Ges.,  1910,  p.  577)  has  sug- 
gested the  use  of  a  solution  of  pyrogallol  as  a  distinctive  re- 
agent for  the  microscopic  study  of  inulin.  The  solution  con- 
sists of  o.ioo  Gm.  Pyrogallol,  alcohol  5  c.c.,  and  5  c.c.  of  hydro- 
chloric acid.  Upon  carefully  heating  sections  treated  with  this 
reagent  the  cells  containing  inulin  are  colored  a  violet  red.  A  simi- 
lar solution  made  with  resorcin  in  place  of  pyrogallol  colors  inulin 
a  cinnabar  red. 

In  taraxacum,  inula,  pyrethrum,  and  other  drugs  inulin  occurs 
in  the  form  of  an  amorphous  mass  having  a  more  or  less  angular 
outline.  The  masses  are  highly  refracting  and  probably  consist 
of  aggregates  of  small  crystals  similar  in  appearance  to  those  of 
mannit  found  in  commercial  manna. 

HESPERIDIN. — Although  not  a  carbohydrate,  hesperidin  is  of 
wide  occurrence  and  separates  in  the  form  of  sphero-crystals  re- 
sembling inulin.  It  is  a  glucoside  (C22H2GO12),  and  it  would 
appear,  from  the  studies  of  Tunmann  (Schweiz.  Woch.  f.  Chem.  u. 
Pharm.,  1909,  p.  794),  that,  like  inulin,  there  are  several  forms 
of  it.  Hesperidin,  like  inulin,  occurs  in  living  cells  in  the  form 
of  a  more  or  less  viscous  fluid.  Upon  the  addition  of  water, 
alcohol,  glycerin,  or  solutions  of  hydrated  chloral  it  separates  in 


152 


A  TEXT-BOOK  OF  BOTANY. 


the  form  of  yellowish  sphere-crystals.  If  the  fresh  plant  material 
is  placed  in  alcohol  the  crystals  separate  in  the  form  of  large 
needles,  often  forming  branching  tufts.  When  examined  by 
means  of  the  micropolariscope,  they  polarize  light  more  or  less 
strongly,  depending  upon  how  the  crystals  were  prepared.  Upon 
quickly  drying  the  plant  material  in  which  it  occurs,  hesperidin 
separates  in  the  form  of  irregular,  slightly  yellowish  clumps,  re- 
sembling those  of  inulin  found  in  the  composite  drugs  of  com- 
merce. If  the  material  is  slowly  dried,  the  crystals  are  decom- 
posed. Crystals  of  hesperidin  have  been  found  in  Citrus  fruits ; 


FIG.  92.  Sphere-crystals  of  inulin.  A,  parenchyma  cells  of  the  root  of  chicory  (Cicho- 
rium  Intybus)  treated  with  alcohol:  a,  numerous  small  globules  shortly  after  the  addition 
of  alcohol;  b,  a  somewhat  later  stage,  showing  the  fusion  of  many  of  the  small  globules  of 
inulin;  c,  crystal  formation  in  the  globules  after  the  alcohol  has  acted  upon  the  cells  for 
24  hours.  B,  sphere-crystals  resembling  starch  grains  formed  in  the  tubers  of  Dahlia  vari- 
abilis  in  alcoholic  material:  in  b,  the  section  has  been  treated  with  nitric  acid,  the  crystal 
aggregate  showing  a  trichiten  structure. — After  Dippel  in  "Das  Mikroskop." 

the  fruit  of  Cocculus  laurifolius;  the  leaves  of  Buchu,  and  Pilo- 
carpus ;  species  of  Mentha,  Hyssopus,  Teucrium,  Satureia,  Tilia ; 
Conium  macula-turn;  Scrophularia  nodosa,  and  stamen  hairs  of 
the  flowers  of  Verbascum.  The  crystals  are  found  especially 
in  the  epidermal  cells  of  bracts.  The  crystals  in  the  hairs  of  the 
flowers  of  Verbascum  are  usually  referred  to  as  a  sugar,  but, 
according  to  the  studies  of  Tunmann,  are  in  the  nature  of  a 
hesperidin. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       153 

If  sections  are  mounted  in  a  small  quantity  of  water  and 
the  latter  replaced  with  dilute  glycerin,  followed  by  concentrated 
glycerin,  then  there  separates  in  the  cells  a  number  of  yellowish 
globules  which  are  highly  refractive  (Fig.  93)  ;  these  globules 
tend  to  unite  in  the  center  and  very  soon  crystallize.  The  sphero- 


FiG.  93.  Hesperidin.  A,  B,  formation  of  sphero-crystals  in  the  epidermal  cells  of  the 
foliage  leaves  of  Linden  upon  the  addition  of  glycerin;  in  A  the  hesperidin  occurs  in  highly 
refracting  globules,  which  in  B  have  united  in  a  large  central  globule  in  which  a  crystal- 
aggregate  has  formed.  C,  crystals  in  stamen  hair  of  the  flower-bud  of  Verbascum.  D, 
crystals  in  the  cells  of  the  upper  epidermis  of  Hyssopus  officinalis.  E,  cells  of  the  upper 
epidermis  of  the  foliage  leaves  of  the  Linden. — After  Tunmann. 

crystal  consists  of  radiating  needles,  the  aggregate  frequently 
being  marked  by  concentric  lamellae,  the  whole  being  surrounded 
by  a  more  or  less  mucilaginous  wall  (Fig.  93).  As  there  are 
other  substances  in  the  cell  the  sphero-aggregate  may  contain 
some  of  these  in  the  interstices.  If  the  crystals  are  formed  slowly 
and  in  the  cold  they  are  apt'  to  be  of  a  yellowish,  or  even  dark 
yellow,  color,  whereas  if  heat  is  employed  and  the  crystallization 


154  A  TEXT-BOOK  OF  BOTANY. 

is  more  rapid  they  are  nearly  colorless  and  dissolve  readily.  The 
crystals  of  hesperidin  are  insoluble  in  water,  alcohol,  glycerin, 
ether,  chloroform,  solutions  of  hydrated  chloral,  dilute  sulphuric 
acid  and  dilute  or  concentrated  hydrochloric  acid  and  nitric  acid. 
They  are  sparingly  soluble  in  ammonia  water  and  hot  acetic  acid. 
Upon  the  addition  of  either  dilute  or  concentrated  solutions  of 
potassium  hydroxide  or  sodium  hydroxide,  hesperidin  dissolves, 
forming  a  yellowish  solution.  With  concentrated  sulphuric  acid 
it  gives  a  deep  yellowish  solution,  which  upon  warming  becomes 
a  reddish-brown.  Sometimes  hesperidin,  as  in  the  stamen  hairs 
of  Verbascum,  is  colored  with  concentrated  sulphuric  acid  only 
a  light  yellow. 

GLYCOGEN  is  a  carbohydrate  allied  to  amylo-dextrin  and  occurs 
commonly  as  a  reserve  food  material  in  the  fungi  and  some 
of  the  Cyanophycece.  It  usually  occurs  in  the  form  of  a  more  or 
less  amorphous  mass  in  the  hyphye  of  the  fungi,  but  occasionally 
is  found  in  definite  granules  resembling  starch.  It  is  supposed 
to  arise  in  plastid  bodies  resembling  leucoplastids,  but  its  general 
formation  is  controlled  by  the  protoplasm.  In  yeast  it  is  found 
in  large  quantities,  sometimes  nearly  filling  the  entire  cell. 

CRYSTALLINE  SUBSTANCES. 

The  sugars  constitute  a  group  of  crystalline  principles  of 
wide  distribution.  They  occur  in  the  cell-sap,  from  which  by 
evaporation  or  on  treatment  with  alcohol  they  may  be  crystallized 
out.  There  are  chemically  two  main  groups:  monosaccharoses 
(formerly  termed  glucoses)  and  disaccharoses  (formerly  the 
saccharoses).  Under  the  former  are  included  the  simple  sugars 
containing  two  or  more  atoms  of  carbon  and  known  as  biose 
(C2H4O2),  etc.  Among  the  pentoses  (C5H10O5)  are  rhamnose, 
a  component  of  certain  glucosides;  fucose,  found  in  fucus  and 
other  brown  algae,  and  chinovite,  occurring  in  certain  Cinchona 
barks.  The  most  important  subdivision  of  the  monosaccharoses 
comprises  the  hexoses  (C6H12O6),  which  include  glucose  and 
fructose,  and  are  widely  distributed ;  d-mannose,  found  in  the 
manna  of  Fraxinus  Ornus  and  obtained  by  hydrolyzing  cellulose, 
especially  the  reserve  cellulose  in  the  seeds  of  the  vegetable  ivory. 
Of  the  disaccharoses  (C^H^On)  cane-sugar  is  the  most  im- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       155 

portant.  In  this  group  are  also  included  maltose,  formed  by  the 
action  of  diastase  on  starch  and  by  the  action  of  ferments  on 
glycogen;  trehalose  or  mycose,  found  in  the  Oriental  Trehala, 
ergot,  Boletus  edulis,  and  other  fungi ;  melibiose,  occurring  in 
Australian  manna  and  in  the  molasses  of  sugar  manufacture; 
touranose,  found  in  Venetian  turpentine  (obtained  from  Larix 
europaa)  and  in  Persian  manna;  and  agavose,  occurring  in  the 
stalks  of  Agave  americana. 

Of  the  numerous  sugars  the  following  are  likely  to  be  met 
with  in  the  microscopical  study  of  drugs  and  economic  products : 

Dextrose  (grape-sugar  or  dextro-glucose)  is  found  in  sweet 
fruits,  the  nectaries  of  the  flowers,  and  stems  and  leaves  of  various 
plants.  It  crystallizes  in  needles  and  varies  in  amount  from  I  to  2 
per  cent,  (in  peaches),  to  30  per  cent,  in  certain  varieties  of 
grapes.  It  also  occurs  in  combination  with  other  principles,  form- 
ing the  glucosides. 

Levulose  (fructose,  fruit-sugar,  or  levo-glucose)  is  associated 
with  dextrose,  occurring  in  some  instances  even  in  larger  quanti- 
ties than  the  latter. 

Sucrose  (saccharose  or  cane-sugar j  is  found  rather  widely 
distributed,  as  in  the  stems  of  corn,  sorghum  and  the  sugar-cane; 
in  roots,  as  the  sugar-beet;  in  the  sap  of  certain  trees,  as  sugar- 
maple  and  some  of  the  palms ;  in  the  nectaries  and  sap  of  certain 
flowers,  as  fuchsia,  caryophyllus,  and  some  of  the  Cactaceae ;  in 
seeds,  as  almond  and  chestnut,  and  in  various  fruits,  as  figs,  mel- 
ons, apples,  cherries.  In  some  plants,  as  in  sugar-cane,  the  yield  is 
as  high  as  20  per  cent.  It  crystallizes  in  monoclinic  prisms  or 
pyramids,  and  forms  insoluble  compounds  with  calcium  and 
strontium. 

Maltose  is  found  in  the  germinating  grains  of  cereals  (see 
Malt)  ;  it  forms  colorless,  needle-shaped  crystals  resembling  those 
of  dextrose,  and  forms  compounds  with  calcium,  strontium,  barium 
and  acetic  acid. 

Trehalose  occurs  in  some  fungi,  as  ergot  and  Amanita  mus- 
caria — the  latter  containing  as  much  as  10  per  cent,  in  the  dried 
plant. 

Mannitol  occurs  in  the  form  of  needles  or  prisms  and  is  found 
in  the  manna  of  Fraxinus  Ornus  to  the  extent  of  90  per  cent.  It 


156 


A  TEXT-BOOK  OF  BOTANY. 


is  also  found  in  some  of  the  Umbelli ferae,  as  Apium  graveolens, 
some  of  the  Fungi  and  sea-weeds,  and  is  rather  widely  distributed 
(Fig.  94). 

Dulcitol,  which  is  closely  related  to  mannitol,  is  found  in 
Eiwnynius  europccus  and  in  most  of  the  plants  of  the  Scroph- 
ulariaceae. 

PERCENTAGE  OF  SUGAR  IN  PLANTS. — No  analysis  is  necessary 
to  indicate  that  most  fruits  contain  quite  a  large  percentage  of 
sugar.  The  following  figures  show  the  amount  of  sugar  in  some 
of  the  more  common  fruits,  the  per  cent,  being  calculated  on 


FIG.  94.     Orthorhombic  crystals  of  Mannitol  (Mannit)  obtained  from  aqueous  solutions: 
A,  large  crystals;  B,  feathery  aggregates  of  needles. 

dry  material:  Apple,  33.16  to  87.73;  apricot,  7.58  to  86.21; 
banana,  6.20  to  21.90;  blackberry,  32.67  to  40.17;  cantaloupe, 
0.27  to  11.98;  cherry,  29.97  to  85.86;  currant,  33.76  to  75.49; 
fig,  10.00  to  29.90 ;  gooseberry,  47.33  to  79.82 ;  grape,  including 
raisin,  67.82  to  83.00;  huckleberry,  12.60  to  46.87;  orange,  36.48 
to  66.91 ;  peach,  6.69  to  74.07;  plum,  15.25  to  78.70;  prune,  32.04 
to  69.46;  pumpkin,  0.15  to  11.98;  and  raspberry,  14.93  to  47.50. 

The  following  percentage  of  sugars  is  present  in  some  of  the 
cereals,  common  vegetables,  etc. :  Asparagus,  0.45  to  3.47 ;  barley, 
5.82  to  8.73;  beet  (garden),  4.20  to  31.45;  beet  (sugar),  3.55  to 
89.61 ;  buckwheat,  1.42  to  1.67;  carrot,  3.62  to  15.30;  cauliflower, 
1.22  to  7.40;  chestnut,  5.22  to  8.52;  cocoa  (cacao),  2.77;  coffee, 
0.20  to  14.50;  corn,  0.96  to  6.77;  cucumber,  0.72  to  1.51; 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       157 

lentils,  2.75;  maple  sap,  2  to  4;  oats,  0.51  to  5.27;  onions,  0.44 
to  14.02;  rye,  0.39  to  9.46;  sorghum  juice,  8.60  to  14.70;  sugar- 
cane juice,  16.00  to  18.10;  spinach,  0.06  to  6.66 ;  turnip  (Swedish), 
5.05  to  9.67;  sweet  potato,  0.32  to  8.42;  tomato,  2.53  to  3.86; 
vanilla,  7.07  to  9.10;  wheat,  0.58  to  5.12. 

HONEY-DEW  is  a  pathological  sugar  formed  as  a  result  of 
the  stings  of  insects  (Aphides  and  Coccideae)  on  the  leaves  of 
certain  trees.  There  are  a  number  of  trees  the  leaves  of  which, 
during  the  summer  time,  are  covered  with  a  thin  layer  of  sugar 
solution.  Among  these  may  be  mentioned  the  linden,  tulip  poplar, 
and  chestnut.  Honey-dew  may  also  be  formed,  according  to 
Bonnier,  without  the  assistance  of  aphides,  and  may  be  seen  oozing 
out  of  the  stomata.  It  may  be  formed  in  such  quantities  that 
it  may  drip  from  trees,  as  in  the  so-called  rain  trees  of  the 
Tropics  (see  Pfeffer,  "  Physiology  of  Plants  "). 

THE  ORIGIN  AND  FORMATION  OF  CARBOHYDRATES. — The  first 
visible  product  of  photosynthesis  is  starch,  and  this  is  sometimes 
called  photosynthetic  starch.  Investigations  during  recent  years 
seem  to  indicate  that  grape-sugar  or  dextrose  is  the  basal  photo- 
synthate,  and  that  from  this  starch  is  later  formed  in  the  plastid. 
This  sugar  is  called  photosynthetic  grape-sugar  to  distinguish  it 
from  the  grape-sugar  found  in  the  cell-sap  of  the  grape,  raisins, 
figs,  etc.  There  is  no  question  but  that  in  the  plastids  starch 
is  readily  formed  from  glucose,  and,  vice  versa,  that  the  starch 
in  the  plastids  is  readily  changed  through  the  agency  of  the 
ferment,  amylase,  into  grape-sugar. 

There  are  four  factors  necessary  for  the  formation  of  a  photo- 
synthetic  carbohydrate  (starch  or  glucose)  by  the  chloroplastids : 
(i)  Light;  and  in  this  condition  it  is  the  energy  of  the  red  and 
blue  rays  of  sunlight  which  are  necessary  to  bring  about  the 
synthesis.  (2)  Carbon  dioxide.  This  compound  must  be  present 
in  about  the  normal  proportions  that  we  find  it  in  the  air,  namely, 
3  parts  in  10,000.  (3)  Water  is  essential,  and  this  is  always  pres- 
ent in  living  cells.  It  is  by  the  dissociation  of  the  CO2  and  H.O 
and  rearrangement  of  the  atoms  that  carbohydrates  are  formed, 
being  either  starch  (C6H10O5)  or  glucose  (C6H12O6),  with  oxy- 
gen as  a  by-product.  These  interactions  may  be  shown  by  the 
following  equations : 


158  A  TEXT-BOOK  OF  BOTANY. 

6CO2  +  5H2O  =  C6H10O5  +  6O2. 

(Starch) 

6C02  +  6H20  =  C6H1206  +  602. 

(Glucose) 

(4)  Certain  mineral  substances  must  be  present,  although,  appar- 
ently, they  take  no  part  in  the  photosynthetic  reaction.  Bokorny 
has  shown  that  compounds  of  potassium  are  essential  to  bring 
about  the  reactions  above  given. 

Some  form  of  iron  has  always  been  considered  necessary  for 
the  development  of  the  green  pigment  or  chlorophyll  in  the  chloro- 
plastid.  While  this  element  may  seem  to  be  necessary  in  water 
culture,  it  is  not  always  essential,  particularly  if  plants  are  grown 
under  control  conditions  in  sand.  The  development  of  chlorophyll 
also  requires  the  presence  of  oxygen.  The  activity  of  the  chloro- 
phyll apparatus  is  further  influenced  by  other  factors,  viz.,  the 
maintenance  of  a  proper  temperature.  It  is  self-evident  that  there 
is  a  minimum  and  maximum  temperature  at  which  photosynthesis 
is  scarcely  perceptible,  and  that  there  is  an  optimum  temperature 
during  which  the  activity  of  the  chloroplastid  is  at  its  height. 
The  latter  varies  with  different  plants,  depending  on  the  climate 
to  which  they  are  either  indigenous  or  naturalized.  In  the  Tropics 
the  optimum  temperature  is  somewhat  higher,  while  in  the  Arctic 
regions  it  is  much  lower.  In  temperate  climates  the  optimum 
varies  between  20°  C.  (68°  F.)  to  30°  C.  (86°  F.). 

From  the  facts  just  given  it  would  appear  that  considerable 
is  known  in  regard  to  the  conditions  and  the  substances  which  are 
concerned  in  the  formation  of  photosynthetic  products.  On  the 
other  hand,  we  know  practically  nothing  of  the  successive  steps  in 
the  formation  of  either  starch  or  glucose  in  the  plant.  Numerous 
experiments  have  been  conducted  and  a  number  of  hypotheses 
have  been  advanced.  According  to  von  Baeyer,  the  first  step 
in  the  process  of  photosynthesis  is  a  reduction  in  the  CO2,  formalde- 
hyde being  formed,  and  this  is  then  polymerized  into  a  carbohy- 
drate, which  is  finally  changed  into  dextrose.  This  may  be  repre- 
sented by  the  following  equations : 

C02  +  H20— >-HCHO  +  02 
xHCHO=('CH2O)x 
6(CHaO)=C6H1206 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       159 

There  are  a  number  of  other  views  which  have  been  advanced. 
Erlenmeyer,  for  instance,  has  suggested  that  instead  of  formalde- 
hyde being  first  formed,  formic  acid  is  the  first  product  of  photo- 
synthesis, hydrogen  peroxide  being  liberated ;  both  of  these  then 
are  decomposed,  formaldehyde  being  formed  according  to  the 
following  equations : 

C02  +  H20  =  HCOOH  +  H202 
HCOOH  +  H2O2  =  HCOH  +  H2O  +  O2 

By  the  further  condensation  of  formaldehyde  as  in  the  hy- 
pothesis of  von  Baeyer,  dextrose  is  formed.  On  the  other  hand, 
Brown  and  Morris  consider  that  the  first  carbohydrate  formed  is, 
in  reality,  cane-sugar,  and  that  from  this,  then,  dextrose  and 
the  other  carbohydrates  are  formed. 

Some  very  interesting  experiments  were  conducted  by  Berthe- 
lot  (Compt.  rend.,  1898,  1900,  etc.),  who  obtained  both  formic 
acid  and  formaldehyde  while  working  with  a  mixture  of  carbon 
dioxide  and  hydrogen.  Later  he  obtained  a  synthetic  carbohy- 
drate, which  on  warming  had  an  odor  of  caramel.  Furthermore, 
when  using  an  excess  of  carbon  monoxide  with  hydrogen,  Berthe- 
lot  obtained  a  substance  closely  related  to  oxy-cellulose.  Lob 
(Ber.  d.  d.  pharm.  Ges.,  1907,  p.  117)  concludes  that  from  formal- 
dehyde, glycolic-aldehyde  (x  CHO.CH2OH)  is  formed;  this  is 
then  followed  by  the  formation  of  glyceric-aldehyde  (CH2OH.CH- 
OH.COH),  which  is  finally  polymerized  into  a  hexose  as  glucose, 
or  even  a  higher  carbohydrate. 

THE  ALKALOIDS  include  a  group  of  organic  bases  which  possess 
remarkable  toxicological  properties.  They  are  compounds  of  car- 
bon, hydrogen,  and  nitrogen  ;  oxygen  is  also  usually  present,  except, 
in  the  liquid  or  volatile  alkaloids,  in  which  it  is  wanting.  They 
are  usually  combined  with  some  organic  acid,  as  malic  acid  or 
tannic  acid.  In  many  cases  the  alkaloids  are  combined  with  acids 
that  are  peculiar  to  the  genus, — e.g.,  aconitic  acid  in  Aconitum, 
meconic  acid  in  Papaver,  etc.  They  are  found  in  a  large  number 
of  plants,  especially  among  the  Dicotyledons,  and  are  rather  char- 
acteristic for  certain  families,  as  those  of  the  genera  Strychnos, 
Cinchona,  Erythroxylon,  Papaver,  etc.  When  present,  alkaloids 
may  be  found  in  any  part  of  the  plant,  but  usually  they  are  most 
abundant  in  certain  definite  regions,  as  roots,  rhizomes,  fruits, 


160  A  TEXT-BOOK  OF  BOTANY. 

seeds,  or  leaves.  Furthermore,  the  amount  is  greatest  at  certain 
stages  of  development,  as  in  the  fully  ripe  seeds,  more  or  less 
immature  fruits,  during  the  resting  periods  of  roots  and  rhizomes, 
and  in  leaves  when  photosynthetic  processes  are  most  active. 
They  occur  in  greatest  amount  in  those  cells  which  are  in  a  poten- 
tial rather  than  an  active  condition,  being  associated  with  starch, 
fixed  oils,  aleurone  grains,  and  other  reserve  products  in  the 
roots,  rhizomes,  and  seeds.  They  are  found  in  fruits  in  greatest 
amount  during  the  development  of  the  seed,  but  after  the  maturing 
of  the  latter  they  slowly  disappear,  as  in  the  opium  poppy  and 
conium. 

The  alkaloids  probably  arise  in  the  protoplasm,  although  they 
may  also  be  formed  from  the  decomposition  of  protein  substances. 
The  fact  that  asparagine,  a  weak  base,  is  usually  present  when 
the  proteins  are  being  formed  from  the  protoplasmic  substances 
and  is  also  present  when  the  proteins  are  being  used  in  the  growth 
of  the  plant,  as  during  the  germination  of  seed,  would  seem  to 
indicate  that  both  views  are  more  or  less  tenable.  The  studies 
of  Lotsy  on  Cinchona  showed  that  alkaloids  are  formed  in  con- 
nection with  photosynthetic  processes  and  that  they  are  subse- 
quently stored  for  the  use  of  the  plant.  On  the  other  hand, 
it  is  rather  interesting  to  note  that  when  cinchona  trees  are 
grown  in  the  hot-house  they  do  not  produce  any  quinine,  and, 
again,  it  is  said  that  the  conium  growing  in  Scotland  does  not 
contain  any  coniine.  From  these  observations  we  must  conclude 
that  alkaloids  are  produced  only  under  certain  conditions,  and 
that  they  are  not  essential  metabolic  substances.  The  fact  that  the 
presence  of  alkaloids  may  be  demonstrated  in  the  thick-walled 
cells  of  the  endosperm  in  nux  vomica  has  led  some  investigators 
to  conclude  that  they  may  arise  in  the  cell-wall.  The  occurrence 
of  alkaloids  at  this  point  is  due  to  their  imbibition  by  the  wall, 
just  as  other  soluble  cell  contents  are  absorbed,  especially  upon  the 
death  of  the  cell. 

MICROCHEMISTRY  OF  ALKALOIDS. — The  alkaloids  occur  in 
rather  large  quantities  in  a  number  of  plants.  Seldom  do  we 
find  them  in  the  form  of  crystals  in  the  plant  cell.  Crystals  of  the 
alkaloid  Piperine  are  not  infrequently  observed  in  the  oil  secre- 
tion cells  of  the  endosperm  of  Piper  nigrum  (Fig.  94,  A).  The 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       161 

alkaloids  form  crystallizable  salts  and,  in  many  instances,  definite 
double  compounds.  Nevertheless,  not  a  great  amount  of  progress 
has  been  made  in  their  detection  and  localization,  either  in  the 
living  plant  or  in  economic  products.  The  reason  for  this  is  that 
other  substances,  as  calcium  oxalate,  may  interfere  with  the 
reactions  forming  crystals  with  the  reagents,  so  that  nothing 
definite  can  be  deduced.  Then  again,  when  an  alkaloid  is  charac- 
terized by  certain  color  reactions,  especially  if  a  rose  or  violet 
color  is  formed,  it  may  be  due  to  the  reaction  of  the  reagent  with 
carbohydrates  or  protein  substance.  For  this  reason  practically 


FIG.  94A.  Crystals  of  Piperine:  A,  cells  of  endosperm  showing  a  single  oil  cell  (b)  in 
which  crystals  of  piperine  have  separated;  (a)  starch  bearing  parenchyma.  B,  piperine 
crystals  separated  from  sections  which  have  been  first  treated  with  alcohol,  and  to  the  oily 
globules  remaining  after  evaporating  the  alcohol,  a  drop  of  distilled  water  has  been  added. 
In  from  fifteen  to  thirty  minutes  there  separate  needles,  short  rods  and  aggregates  of 
piperine. — After  Molisch's  work  on  Histochemie. 

there  are  only  a  few  instances  where  satisfactory  results  are 
obtained  in  the  study  of  alkaloids  in  plant  tissues.  These,  for  the 
most  part,  have  been  obtained  in  connection  with  the  dried  mate- 
rials of  commerce.  As  it  is  very  important  that  these  studies 
should  be  carried  further,  a  few  illustrations  may  be  given. 

Hydrastis  contains  two  alkaloids  in  considerable  quantities 
which  form  definite  salts  with  nitric  and  sulphuric  acids.  Fur- 
thermore, this  plant  does  not  contain  calcium  oxalate,  so  that  the 
crystals  formed  upon  the  addition  of  mineral  acids  could  not  be  of 
either  the  nitrate  or  sulphate  of  calcium,  and  if  in  other  respects 
they  corresponded  to  the  sulphates  and  nitrates  of  the  alkaloids 
peculiar  to  hydrastis,  then  the  crystals  must  be  salts  of  the  alka- 
loids. If  sections  of  the  fresh  rhizome  of  hydrastis  or  the  moist- 
ii 


1 62 


A  TEXT-BOOK  OF  BOTANY. 


ened  drug  are  mounted  directly  in  sulphuric  acid,  there  separate 
very  soon  small  acicular  or  rod-shaped  crystals  of  berberine  and 
hydrastine  (Fig.  95).  This  is  one  of  the  most  satisfactory  of 
microchemical  tests  of  the  alkaloids  that  is  known,  and  Leuff  has 
shown  that  they  can  be  readily  determined  even  in  the  endosperm 
cells  in  the  seeds  of  hydrastis  (Pharm.  Post,  1913,  p.  977). 

Caffeine  is  an  alkaloid  which  is  rather  widely  distributed,  and 
its  presence  can  be  easily  determined,  in  dried  material  as 
coffee  seeds,  in  several  ways.  ( i )  It  may  be  sublimed,  the  long, 


\ 


B 


FIG.  95.  Alkaloids  in  Hydrastis:  A,  prismatic  crystals  which  separate  after  a  time 
on  treatment  of  sections  of  the  rhizome  of  hydrastis  or  its  powder  with  sulphuric  acid;  B, 
the  separation  of  needle-shaped  crystals  of  the  sulphates  of  the  alkaloids  in  the  paren- 
chyma cells  of  hydrastis  upon  treatment  with  sulphuric  acid. 

silky  needles  of  caffeine  being  deposited  upon  a  watch  crystal 
or  a  microscopic  slide.  (2)  Similar  crystals  may  separate  from 
aqueous  or  hydro-alcoholic  mounts  of  the  material.  (3)  The  most 
satisfactory  method  for  the  detection  of  caffeine  is  to  form  a 
double  salt  with  gold  chloride,  the  crystals  of  which  are  very 
characteristic  (Fig.  96).  The  test  may  be  applied  to  coffee  seeds, 
cola  nuts,  tea  leaves,  guarana,  etc.,  as  follows :  Sections  are  placed 
in  strong  hydrochloric  acid  and  slightly  heated ;  then  one  or  two 
drops  of  a  solution  of  gold  chloride  are  added  and  the  sections 
pushed  to  one  side,  allowing  the  liquid  to  evaporate.  Near  the 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       163 

edge  of  the  residue  branching  groups  of  needles  of  caffeine  gold 
chloride  separate.  Cocaine  is  another  alkaloid  which  forms  char- 
acteristic crystals,  and  the  double  salt  of  the  chloride  with  palladous 
chloride  is  very  characteristic  (Fig.  97).  The  crystals  of  the 
latter  may  be  prepared  in  the  same  manner  as  caffeine,  except 
that  to  the  sections  of  coca  leaves  or  the  powdered  material  a 
smaller  quantity  of  hydrochloric  acid  is  added. 


FIG.  96.     Caffeine  gold  chloride;   crystals  formed  on  the  addition  of  a  solution  of  gold 
chloride  to  a  dilute  aqueous  solution  of  caffeine. 

PROPERTIES  OF  ALKALOIDS. — In  the  microchemical  study  of 
the  cell-contents  it  is  important  to  bear  in  mind  that  the  alkaloids 
possess  certain  characteristic  properties  and  give  definite  reactions 
with  the  so-called  "  alkaloidal  reagents."  The  alkaloids  occur  in 
combinations  with  acids  forming  salts  which  are  mostly  soluble  in 
water  or  in  alcohol,  and  consequently  may  be  extracted  by  means 
of  these  solvents.  From  the  latter  well-characterized  crystals 
may  be  easily  formed.  The  free  alkaloid  may  be  separated  from 
solutions  of  their  salts  in  water  by  the  addition  of  alkalies,  but  it 
is  usually  important  that  the  solutions  of  the  latter  be  not  in 
excess,  as  otherwise  the  separated  alkaloids  may  dissolve.  With 


164 


A  TEXT-BOOK  OF  BOTANY. 


few  exceptions,  as  Berberine  and  Sanguinarine,  they  form  mostly 
colorless  crystals.  Among  the  alkaloidal  reagents  giving  charac- 
teristic precipitates  the  following  may  be  mentioned.  Phospho- 
molybdic  acid  ( Sonnenschein's  Reagent)  gives  with  nearly  all  of 
the  alkaloids  a  yellow,  insoluble  amorphous  precipitate.  Potas- 


FIG.  97.  Cocaine:  A,  monoclinic  crystals  of  cocaine;  B,  orthorhombic  crystals  of  co- 
caine hydrochloride ;  C,  monoclinic  crystals  of  cocaine  hydrochloride  and  palladous  chloride; 
D,  skeleton  aggregates  of  cocaine  hydrochloride  and  palladous  chloride. 

sium  mercuric  iodide  (Mayer's  Reagent)  precipitates  many  of 
the  alkaloids  in  even  dilute  solutions,  the  precipitates  being  usually 
yellowish-white  and  more  or  less  flocculent.  Wagner's  Reagent, 
or  iodine  dissolved  in  a  solution  of  potassium  iodide,  is  another 
reagent  that  precipitates  nearly  all  the  alkaloids.  The  precipi- 
tates are  of  a  reddish  or  reddish-brown  color,  and  are  more 
readily  formed  in  acidulated  solutions.  From  alcoholic  solutions 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       165 

crystalline  double  compounds  may  be  formed.  Picric  acid  forms 
characteristic  crystals  with  a  number  of  the  alkaloids.  Wormley's 
Reagent,  or  a  solution  of  bromine  in  hydrochloric  acid,  gives 
definite  microscopic  crystals  with  some  of  the  alkaloids,  as  atro- 
pine,  hyoscyamine,  and  veratrine.  Auric  chloride  and  platinic 
chloride  both  form  characteristic  double  salts  with  a  number  of 
the  alkaloids.  There  are  a  number  of  other  reagents  which  are 
used  in  the  study  of  the  localization  of  alkaloids  in  plants.  Most 
of  these  depend  upon  certain  color  reactions.  While  it  is  true 
that  the  alkaloids  give  rather  striking  colors  with  certain  reagents, 
yet,  as  a  rule,  they  are  of  little  value  except  when  the  alkaloids 
are  in  a  pure  condition.  This  same  objection  holds,  but  with  some- 
what less  force,  to  the  employment  of  the  alkaloidal  reagents 
just  mentioned. 

FAMILIES  YIELDING  ALKALOIDS. — It  is  very  difficult  to  deter- 
mine from  the  literature  of  the  analyses  as  to  how  widely  distrib- 
uted alkaloids  are  in  plants.  Time  and  again  principles,  which 
give  definite  reactions  with  certain  alkaloidal  reagents,  are  subse- 
quently shown  to  be  other  than  alkaloids.  In  enumerating  the 
families  in  which  alkaloids  occur  we  do  not  mean  to  say  that 
they  are  lacking  in  the  families  not  mentioned  here.  Alkaloids 
are  seldom  found  in  the  Cryptogams,  being  confined,  with  few 
exceptions,  to  the  poisonous  fungi,  as  Amanita  of  the  Agaricacae. 
Among  the  Monocotyledons  they  are  found  in  the  Palmae  and  the 
Liliaceae.  They  are  more  widely  distributed  in  the  Dicoty- 
ledons, occurring  in  the  following  families :  Piperaceae,  Chenopo- 
diaceae,  Ranunculaceae,  Berberidaceae,  Menispermaceae,  Lauraceae, 
Papaveraceae,,  Leguminosae,  Erthroxylaceae,  Rutaceae,  Aquifolia- 
ceae,  Sapindaceae,  Sterculiaceae,  Punicaceae,  Umbelli ferae,  Logania- 
ceae,  Apocynaceae,  Solanaceae,  Rubiaceae,  and  Lobeliaceae. 

THE  AMOUNT  OF  ALKALOIDS  in  plants  varies  under  different 
climatic  conditions  and  is  also  very  much  influenced  by  culti- 
vation (see  chapter  on  "Cultivation  of  Medicinal  Plants"). 
For  these  reasons  there  is  a  wide  range  in  the  alkaloidal  content  of 
drug  products,  and,  as  the  alkaloids  are  among  the  most  poisonous 
constituents  known,  the  various  pharmacopoeias  have  set  alkaloidal 
standards.  At  the  International  Conference  for  the  Unification  of 
Pharmacopoeial  Formulae  for  Potent  Medicaments  held  in  Brtts- 


166  A  TEXT-BOOK  OF  BOTANY. 

sels  in  1902  a  protocol  was  prepared  designating  the  strength  of 
the  various  galenicals.  Unfortunately,  a  standard  for  the  alka- 
loidal  content  of  drugs  was  not  also  established,  and  consequently 
in  the  several  pharmacopoeias  there  is  still  some  variation  in  drug 
standards.  For  percentage  of  alkaloids  in  different  drugs  and  their 
variation,  consult  Volume  II,  treating  of  Pharmacognosy. 

CHEMICAL  CLASSIFICATION  OF  ALKALOIDS. — The  chemical 
study  of  the  alkaloids  shows  that  each  plant  contains  not  one  but 
a  number  of  alkaloids,  cinchona  bark  and  the  opium  poppy  yield- 
ing not  less  than  twenty  different  alkaloids.  As  their  chemical 
constitution  is  not  well  known,  it  is  customary  even  for  the  chemist 
to  group  them  into  certain  natural  classes,  as  the  alkaloids  of 
conium,  tobacco  alkaloids,  the  cinchona  alkaloids,  opium  alka- 
loids, etc.  They  may  also  be  grouped  into  certain  fundamental 
groups,  according  to  their  nuclear  structure  derived  from  their 
probable  constitution.  While  the  natural  classification  may  be 
more  convenient,  it  will  be  replaced  by  a  classification  based  on 
chemical  constitution  when  our  knowledge  of  this  class  of  sub- 
stances is  extended.  From  studies  thus  far  made  the  following 
groups  of  alkaloids  may  be  recognized : 

PYRIDINE  GROUP. — Alkaloids  derived  from  pyridine  (C5H5N) 
are  found  in  Conium  maculatum,  Piper  nigrum,  and  other  species 
oi  Piper,  Trigonella  Focnum  gracum,  Areca  Catechu,  Beta  vul- 
garis,  Nicotiana  Tabacum,  Pilocarpus  Jaborandi  and  other  species 
of  Pilocarpus,  Lupinus,  Laburnum,  and  other  genera  of  the 
Leguminosa.  This  group  includes  the  liquid  or  volatile  alkaloids. 

PYRROLIDINE  GROUP. — Derivatives  of  Pyrrolidine  (C4H8NH) 
occur  in  Atropa,  Hyoscyamus,  Datura,  Scopolia  and  other  genera 
of  the  Solanace<z,  Erythroxylon  Coca,  and  Punica  Granatum. 

QUINOLINE  GROUP. — Alkaloids  with  a  Quinoline  nucleus 
(C9H7N)  are  obtained  from  cinchona  bark  and  nux  vomica. 

ISOQUINOLINE  GROUP. — Isoquhioline  is  isomeric  with  quino- 
line;  alkaloids  with  this  nucleus  are  found  in  the  opium  poppy, 
Hydrastis  canadensis,  Berberis  vulgaris,  Menispermum  canadense 
and  quite  a  number  of  genera  in  the  closely  related  families  of 
Ranunculacece,  as  well  as  in  some  other  plants. 

PHENANTHRENE  GROUP. — Morphine  and  codeine,  closely  re- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       167 

lated  alkaloids  in  opium,  probably  contain  the  Phenanthrene 
nucleus  (C14H10). 

PURINE  GROUP. — Caffeine,  the  characteristic  alkaloid  of 
coffee,  tea,  and  guarana,  as  well  as  theobromine  associated  with 
caffeine  in  cacao  and  kolanut,  are  derivatives  of  Purine  (C5H4N). 

AMINO-ACID  GROUP. — Asparagine,  or  the  monamide  of  aspartic 
acid,  is  very  widely  distributed  throughout  the  plant  kingdom. 

Consult  J.  W.  Bruhl,  "  Die  Pflanzen-Alkaloide  " ;  A.  Pictet, 
"  The  Vegetable  Alkaloids,"  translation  by  H.  C.  Biddle ;  O.  A. 
Oesterle,  "  Grundriss  der  Pharmakochemie." 

ASPARAGINE  (C4H8N2  +  H2O)  (/?-asparagine,  the  monamide  of 
aspartic  acid)  is  an  amido  compound  which  is  most  widely  distrib- 
uted throughout  the  vegetable  kingdom.  It  is  found  not  only  in 
reserve  organs  as  the  tubers  of  the  potato  and  dahlia,  the  roots 
of  althaea,  belladonna,  etc.,  and  the  seeds  of  the  chestnut  tree, 
but  it  also  occurs  in  young  shoots  as  of  asparagus  and  in  peas, 
beans,  and  other  members  of  the  Leguminosae.  Asparagine  has 
also  been  detected  in  some  of  the  fungi  as  the  Agaricineae  and  cer- 
tain of  the  Myxomycetes.  Unlike  certain  derivatives  of  urea,  it  is 
a  plastic  product  playing  a  very  important  role  in  plant  metabolism. 
On  account  of  its  crystalline  character  and  solubility  in  water, 
it  is  classed  among  the  translocatory  substances,  appearing  not 
only  when  proteins  are  being  utilized  by  the  plant,  but  when 
they  are  being  formed.  The  crystals  of  asparagine  are  formed 
rather  easily  from  the  expressed  juices  of  young  shoots,  and  may 
be  obtained  even  in  sections  upon  mounting  them  in  glycerin. 
The  crystals  vary  in  length  from  0.3  mm.  to  15  mm.  (Fig.  98). 

Asparagine  occurs  in  two  forms,  one  of  which  is  laevorotatory 
and  the  other  dextro-rotatory;  the  former  is  the  one  usually 
present  in  plants.  At  17.5  °  C.,  I  part  of  asparagine  is  soluble 
in  47  parts  of  distilled  water;  at  98°  C.,  I  part  is  soluble  in  1.9 
parts  of  distilled  water. 

THE  GLUCOSIDES  or  Glycosides  are  a  class  of  plant  substances 
which  under  the  influence  of  ferments  split  up  into  a  number  of 
substances,  one  of  which  is  always  glucose  (dextrose)  or  an  analo- 
gous compound.  Van  Rijn  has  proposed  the  class  name  Glykoside 
for  all  substances  of  this  group,  restricting  the  name  glucoside 
to  those  which  yield  glucose  on  hydrolysis.  The  glucosides  are 


168 


A  TEXT-BOOK  OF  BOTANY. 


always  associated  in  the  plant  cell  with  the  special  ferments 
which  are  capable  of  decomposing  them.  There  are  other  sub- 
stances which  have  the  property  of  breaking  up  the  glycosides, 
viz.,  dilute  acids  and  alkalies.  Of  the  mineral  acids,  dilute 
sulphuric  acid  and  dilute  hydrochloric  acid  are  the  most  effective. 
They  do  not,  however,  always  produce  the  same  results  on  the 
same  glucoside,  as  sometimes  one  acid  works  better  than  the 
other.  Some  glucosides  are  hydrolyzed  by  the  use  of  strong 


FIG.  98.  Microphotograph  of  the  rhombic  prisms  of  Asparagine  (amido-succinamic 
acid) ,  which  is  rather  widely  distributed  in  the  vegetable  kingdom.  From  aqueous  solution 
the  smaller  crystals  are  combinations  of  base  and  prism  (a) ;  one  or  both  of  the  acute  angles 
may  be  truncated  on  the  faces  of  the  brachydome  (b) ;  in  the  larger  crystals  (c)  the  brachy- 
dome  is  more  developed  and  is  either  equidimensional  or  elongated  on  the  a -axis. 

organic  acids,  as  oxalic  acid  and  citric  acid.  In  view  of  the  fact 
that  most  glucosides  require  the  presence  of  water  in  addition 
to  the  presence  of  the  ferment  to  produce  an  interaction,  they 
are  looked  upon  as  ether  or  ester  derivatives.  This  view  is 
strengthened  by  a  careful  study  of  the  glucosides  which  have 
been  prepared  synthetically,  but  it  is  not  known  in  what  manner 
the  glucoside  is  united  with  the  other  compounds  making  up  the 
natural  glucosides. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       169 

DISTRIBUTION  OF  GLUCOSIDES. — This  class  of  substances  has 
only  been  isolated  in  the  Dicotyledons,  being  present  in  the  Pina- 
ceae,  Gramineae,  Liliaceae,  Iridaceae,  Salicaceae,  Fagaceae,  Moraceae, 
Urticaceae,  Proteaceae,  Santalaceae,  Polygonaceae,  Caryophyllaceae, 
Ranunculaceae,  Magnoliaceae,  Calycanthaceae,  Anonaceae,  Moni- 
miaceae,  Cruciferae,  Saxif  ragaceae,  Rosacese,  Leguminosae,  Tropaeo- 
laceae,  Linaceae,  Rutaceae,  Simarubaceae,  Polygalaceae,  Anacar- 
diaceae,  Corynocarpaceae,  Aquifoliaceae,  Celastraceae,  Hippocas- 
tanaceae,  Sapindaceae,  Rhamnaceae,  Vitaceae,  Tiliaceae,  Malvaceae, 
Theaceae,  Dipterocarpaceae,  Cistaceae,  Caricaceae,  Datiscaceae, 
Thymelaeaceae,  Lythraceae,  Punicaceae,  Combretaceae,  Myrtaceae, 
Araliaceae,  Ericaceae,  Primulaceae,  Sapotaceae,  Oleaceae,  Logania- 
ceae,  Gentianaceae,  Apocynaceae,  Asclepiadaceae,  Convolvulaceae, 
Hydrophyllaceae,  Boraginaceae,  Verbenaceae,  Labiatae,  Solanaceae, 
Scrophulariaceae,  Bignoniaceae,  Orobanchaceae,  Globulariaceae, 
Rubiaceae,  Caprifoliaceae,  Cucurbitaceae,  and  Compositae. 

CHEMICAL  CLASSIFICATION. — The  natural  glucosides  may  be 
grouped  either  according  to  the  nature  of  the  sugar  formed  on 
hydrolysis  or  their  probable  organic  derivatives.  Most  glucosides 
yield  either  dextrose  or  rhamnose.  (i)  Of  the  dextrose-gluco- 
sides  the  following  may  be  mentioned :  yEsculin,  arnygdalin,  arbu- 
tin,  coniferin,  fraxin,  gaultherin,  gossypetin,'  gynocardin,  indican, 
iridin,  linamarin,  phloridzin,  populin,  prulaurasin,  ruberithrinic 
acid,  salicin,  sambunigrin,  saponarin,  serotin,  sinalbin,  sinigrin, 
and  syringin.  (2)  Of  the  rhamnose-glucosides  the  following  may 
be  mentioned:  Baptism,  datiscin,  frangulin,  fustin,  glycyphyllin, 
and  quercitrin.  (3)  There  are  a  few  glucosides  which  yield 
peculiar  sugars,  as  apiin,  which  on  hydrolysis  gives  apiose  and 
dextrose;  barbaloin  forms  d-arabinose;  convolvulin  yields  rho- 
deose  and  dextrose ;  digitalin  forms  digitalose  and  dextrose ; 
digitonin  forms  galactose  and  dextrose;  digitoxin  yields  digi- 
toxose;  gentiin  yields  xylose  and  dextrose;  hesperidin  forms 
rhamnose  and  dextrose,  which  are  also  formed  from  naringin  and 
rutin ;  robinin  forms  galactose  and  rhamnose ;  strophanthin  yields 
rhamnose  and  mannose ;  vicianin  forms  arabinose  and  dextrose ; 
and  xanthorhamnin  yields  galactose  and  rhamnose. 

Rosenthaler  (Pharm.  Zentralh.,  1907,  p.  94)  has  attempted 
to  group  the  glucosides,  according  to  the  constitution  of  the  non- 


1 70  A  TEXT-BOOK  OF  BOTANY. 

sugar  substance  formed  on  the  hydrolysis  of  the  glucoside.  He 
has  given  the  non-sugar  substances  the  class  name  of  "  Aglykone," 
and  groups  the  glucosides  accordingly  into  the  following  three 
classes:  I.  Glucosides  without  Nitrogen  Aglykones.  II.  Gluco- 
sides with  Nitrogen  Aglykones.  III.  Glucosides  with  Nitrogen 
and  Sulphur  Aglykones.  Class  I  are  further  subdivided  into 
whether  they  yield  alipathic,  aromatic,  or  other  derivatives ;  each 
of  these  again  is  further  subdivided  into  a  number  of  subgroups. 
Among  the  alipathic  aglykones  are  included  the  glucosides,  jalapin 
and  convolvulin.  The  glucosides  with  aromatic  aglykones  are 
subdivided  as  follows:  (A)  Those  yielding  benzol  derivatives 
and  include  arbutin,  salicin,  populin,  gaultherin,  etc.  (B)  Deriva- 
tives containing  the  styrol  nucleus  include  coniferin,  daphnin,  ses- 
culin,  scopolin,  fraxin,  naringin,  and  hesperidin.  (C)  Derivatives 
containing  anthracene  in  their  constitution,  as  f  rangulin,  morindin, 
and  the  glucosides  of  emodin,  rhein,  etc.  (D)  Glucosides  which 
are  derivatives  of  flavon  include  apiin,  fustin,  quercitrin,  rutin, 
xanthorrhannin.  II.  The  glucosides  with  Nitrogen  Aglykones 
include  a  number  of  cyanogenetic  glucosides,  of  which  amygdalin 
is  the  representative.  III.  The  glucosides  with  Nitrogen  and 
Sulphur  Aglykones  include  sinigrin  and  sinalbin  found  in  the 
genus  Sinapis  and  other  genera  of  the  Cruciferae.  (Consult 
J.  J.  L.  van  Rijn,  "  Die  Glykoside  " ;  O.  A.  Oesterle,  "  Grundriss 
der  Pharmakochemie.") 

PROPERTIES  OF  THE  GLUCOSIDES. — Like  the  alkaloids,  some  of 
the  glucosides  are  highly  toxic.  Among  those  that  possess  a  high 
degree  of  toxicity  may  be  mentioned  convallamarin,  digitalin,  scil- 
lain,  strophanthin,  sapotoxin,  etc.  They  are  soluble  in  water, 
alcohol,  ethyl  acetate,  and  chloroform,  and  insoluble  in  ether.  The 
aqueous  solutions  are  neutral  or  but  faintly  acid.  Glucosides 
may  be  separated  from  solutions  of  salts  of  the  alkaloids  owing 
to  the  fact  that  they  are  soluble  in  chloroform  and  some  other 
of  the  immiscible  solvents,  providing  the  solution  is  slightly  acid. 
Most  of  the  glucosides  form  well-developed  crystals  and  may  be 
studied  with  a  petrographical  microscope  (Fig.  99).  There  is 
no  special  class  of  reagents,  as  with  the  alkaloids,  used  in  their 
detection ;  on  the  other  hand,  some  of  them  give  strikingly 
distinct  color  reactions  whereby  they  may  be  detected  in  the 


FIG.  99.      Salicin.     Orthorhombic  crystals  from  alcoholic  solution. 


FIG.   100.      Cocaine  hydrochloride.     Aggregates  from  aqueous  solution. 

CRYSTALS  IN  POLARIZED  LIGHT  (Crossed  nicols). 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       171 

tissues  of  the  plant.  With  very  few  exceptions,  however,  the 
color  reactions  are  not  satisfactory. 

MICRO-CHEMISTRY  OF  GLUCOSIDES. — Although  the  glucosides 
upon  extraction  from  the  plant  tissues  form  well-defined  crystals 
(Fig.  99),  they  have  not  been  identified  as  such  in  the  plant. 
A  few  have  been  identified  by  giving  distinct  color  reactions  with 
certain  reagents.  The  glucoside  strophanthin  can  be  detected  in 
the  seeds  of  Strophanthus  hispidus.  This  glucoside  is  colored  a 
brilliant  green  with  sulphuric  acid  and  is  confined  to  the  cells  of 
the  endosperm.  The  test  is  carried  out  as  follows:  Sections 
are  mounted  first  in  water  and  then  transferred  to  a  drop  of 
sulphuric  acid  contained  on  the  same  slide,  when  the  cells  con- 
taining strophanthin  are  colored  a  bright  green.  Saponin  is  an- 
other glucoside  which,  it  is  stated,  may  be  readily  detected  in 
plant  cells,  giving  a  reddish  color  reaction  with  sulphuric  acid. 
Lafon's  reagent  also  may  be  applied  for  the  detection  of  saponin ; 
this  consists  in  the  use  of  two  solutions:  (a)  equal  volumes  of 
alcohol  and  sulphuric  acid;  (b)  a  very  dilute  solution  of  ferric 
chloride.  The  sections  are  placed  in  solutions  (a)  and  then  a 
drop  of  solution  (b)  is  added.  Cells  containing  saponin  are  col- 
ored red,  changing  to  violet,  becoming  brownish-blue,  or  brown 
upon  the  addition  of  ferric  chloride.  Coniferin,  the  glucoside 
found  in  the  cells  of  pine  and  other  Coniferous  trees,  is  colored 
red  with  sulphuric  acid ;  it  also  gives  a  characteristic  reaction  on 
treatment  of  the  section  first  with  phenol,  followed  by  sulphuric 
acid  or  hydrochloric  acid,  it  becoming  a  deep  blue  almost  instantly. 

THE  SAPONINS  are  a  group  of  glucosides  which  possess  the 
common  property  of  forming  a  froth  on  shaking  their  aqueous 
solutions,  and  are  present  in  the  "  soap-plants,"  which  have 
been  widely  used  as  detergents.  The  saponins  also  dissolve  the 
red  blood-corpuscles,  and  for  this  reason  are  considered  to  be 
toxic  substances.  They  have  been  found  in  the  cell-sap  of  a  large 
number  of  plants,  occurring  in  parenchyma  cells  and  medullary 
rays  of  roots  and  stems,  the  secretion  cells  and  secretion  reser- 
voirs of  leaves,  and  all  parts  of  fruits  and  seeds.  A  large  number 
of  principles  have  been  isolated  from  different  plants,  some  of 
these  being  given  distinct  names,  but  the  majority  of  them  are 
homologous  substances  having  the  general  formula  CnH2n_8O10. 


172  A  TEXT-BOOK  OF  BOTANY. 

On  account  of  some  of  the  saponin-containing  plants  being  added 
to  beverages  and  used  as  emulsifying  agents,  the  toxicity  of  a 
number  of  the  saponins  has  been  studied,  those  which  are  highly 
poisonous  being  known  as  sapotoxins.  The  following  are  some 
of  the  plants  which  contain  sapotoxin:  Quillaja  Saponaria  (9  per 
cent.),  Agrostemma  Githago  (6.5  per  cent.),  Saponaria  officinalis 
(4  to  5  per  cent),  and  Poly  gala  Senega  (2.5  per  cent.). 

Saponins  have  been  found  in  more  than  a  hundred  different 
plants,  including  one  or  more  genera  of  the  following  families: 
Liliaceae,  Dioscoreaceae,  Araceae,  Chenopodiaceae,  Phytolaccaceae, 
Caryophyllaceae,  Berberidaceae,  Magnoliaceae,  Ranunculaceae, 
Bixaceae,  Theaceae,  Rutaceae,  Zygophyllaceae,  Meliaceae,  Simaru- 
baceae,  Sapindaceae,  Hippocastanaceae,  Melianthaceae,  Polygalaceae, 
Pittosporaceae,  Rhamnaceae,  Saxifragaceae,  Passifloraceae,  Big- 
noniaceae,  Myrtaceae,  Rosaceae,  Leguminosae,  Primulaceae,  Sapo- 
taceae,  Oleaceae,  Solanaceae,  Scrophulariaceae,  Rubiaceae,  and 
Compositae. 

'Gluco-alkaloids  represent  a  class  of  compounds  intermediate 
between  the  alkaloids  and  glucosides,  possessing  characteristics 
of  each.  To  this  class  belong  achilleine,  found  in  various  species 
of  Achillea,  and  also  solanine,  found  in  a  number  of  species  of 
Solanum. 

FUNCTIONS  OF  ALKALOIDS  AND  GLUCOSIDES. — In  the  growth 
of  the  plant  there  must  not  only  be  an  adaptation  to  the  external 
conditions  and  provision  made  to  protect  the  plant  against  tem- 
pests, drought,  excessive  light,  extreme  temperatures,  etc.,  but 
the  plant  must  protect  itself  from  diseases  as  well  as  from  the 
depredations  of  animals.  As  a  rule,  plants,  particularly  of  the 
tropics,  depend  on  their  own  power  to  repair  any  injury  to  which 
they  may  be  subjected.  Nevertheless,  there  are  many  plants 
which  produce  poisonous  substances,  and  these  are  usually  sup- 
posed to  have  the  function  of  protecting  them  from  various  dis- 
eases, as  well  as  attack  by  herbivorous  animals.  Many  of  the 
alkaloids  and  glucosides  are  apparently  aplastic  substances, — i.e., 
are  formed  either  occasionally  or  continually  as  unavoidable  by- 
products of  metabolism,  or  are  produced  for  special  purposes. 
Some  of  these  principles,  as  asparagine,  an  alkaloid,  and  hesperi- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       173 

din,  a  glucoside,  are  not  only  products  of  constructive  metabolism, 
but  are  entirely  reassimilated. 

SUBLIMABLE  PRINCIPLES. — Quite  a  number  of  plant  principles 
are  capable  of  being  sublimed.  Not  only  is  this  true  when  they  are 
in-  the  pure  state,  but  also  when  they  are  associated  with  other 
compounds  in  the  plant  cell.  This  fact  is  of  very  great  interest  in 
the  examination  of  commercial  articles  and  also  in  the  study  of 
the  localization  and  distribution  of  plant  constituents.  The  method 
of  procedure  is  very  simple,  and  a  small  quantity  of  material 
only  is  necessary,  usually  from  0.020  to  0.050  Gm.  being  required. 
In  the  study  of  leaves  a  fragment  about  10  square  millimeters  is 
sufficient.  The  material  is  dried,  either  cut  up  or  more  or  less 
comminuted  and  placed  in  a  small  watch  crystal,  the  latter  being 
covered  either  with  a  slide  or  another  watch  crystal  for  the  deposi- 
tion of  the  sublimate.  The  watch  crystal  containing  the  material 
is  carefully  heated  either  on  a  sand  bath  or  on  a  bath  containing 
sulphuric  acid  (Figs.  101  to  104). 

Rosenthaler  (Ber.  d.  d.  pharm.  Ges.,  1911,  p.  338)  has  sug- 
gested in  the  examination  of  powdered  drugs  a  specially  con- 
structed apparatus.  A  small  quantity  of  the  powder  is  intro- 
duced by  means  of  a  long  funnel  into  a  suitable  tube,  so  that  n®ne 
of  it  comes  into  contact  with  the  side  walls.  The  powder  should  be 
covered  with  a  layer  of  asbestos  to  prevent  any  of  it  being  carried 
up  mechanically.  The  tube  is  closed  with  a  rubber  stopper  having 
two  holes,  one  of  which  carries  a  doubly  bent  tube  leading  to  a 
small  vessel  acting  as  a  receiver,  the  other  carrying  a  tube  con- 
nected with  an  air-pump.  The  air  is  exhausted  and  the  tube  con- 
taining the  drug  is  heated  in  a  bath  of  sulphuric  acid  or  paraffin. 
A  sublimate  will  form  in  the  upper  part  of  the  tube  containing 
the  material,  and  distillation  products  will  pass  into  the  tube 
acting  as  a  receiver  and  can  be  tested  with  various  solvents  and 
reagents.  Plants  containing  thein,  vanillin,  and  cumarin  may  be 
examined  by  direct  sublimation  in  a  watch  crystal.  Substances 
which  yield  tarry  distillate,  as  cinchona,  hydrastis,  piper,  etc., 
probably  are  better  examined  using  the  apparatus  described  by 
Rosenthaler. 

Tunmann  (Ber.  d.  d.  pharm.  Ges.,  1911,  p.  312)  examined  a 
number  of  plants  of  the  Ericaceae  and  found,  by  the  microsublima- 


174 


A  TEXT-BOOK  OF  BOTANY. 


tion  method,  that  they  contained  arbutin.  The  latter  is  a  rather 
widely  distributed  glucoside  in  this  family  and  yields  upon  treat- 
ment with  solutions  of  emulsin  or  hydrochloric  acid  the  sublimable 
principle  hydrochinon.  The  latter  forms  prisms  and  plates  and 
may  be  further  examined  with  acetone  solution,  dilute  solutions  of 


FlG.  10 1.  Alkaloids  of  hydrastis  obtained  by  microsublimation.  The  method  fol- 
lowed by  Tunmann  is  to  mix  from  o.oio  to  0.050  Gm.  of  powdered  hydrastis  with  a  drop  of 
water  upon  a  glass  slide  and  heat  to  a  temperature  of  80°  to  95°  C.  The  sublimate  consists 
of  a  number  of  radiating  particles  in  which  different  types  of  crystals  very  soon  separate  (A). 
The  microsublimate  may  be  further  treated  with  alcohol  and  a  solution  of  potassium  iodide, 
when  crystals  of  hydrastine  (B)  and  needle-shaped  crystals  of  berberine  (C)  form. — After 
Tunmann  in  Gehe  &  Co.'s  Handelsbericht,  1912. 

ferric  chloride  and  ammonia  water.  Arbutin  occurs  in  the 
leaves  of  Arctostaphylos  Uva-ursi,  Vaccinlum  Myrtillus,  Kalmia 
angustifolia,  and  Pyrola  rotundifolia. 

Rosenthaler  obtained  definite  crystals  in  the  microsublimation 
or  pyro-analysis  of  the  following  drugs :  cinchona,  uva-ursi,  f ran- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       175 

gula,  rhamnus  purshianus,  rheum,  hydrastis,  opium,  cubeba,  piper, 
anisum,  senna,  radix  scammoniae,  chrysarobium,  rheum  rhaponti- 


FIG.  102.  Microsublimate  crystals  of  alkaloids  in  hydrastis:  A,  White  crystals  of 
hydrastine  formed  upon  the  addition  of  chloroform  to  the  sublimate.  B,  Type  crystals 
obtained  on  the  microsublimation  of  pure  hydrastine  hydrochloride.  C,  Type  crystals 
obtained  on  the  microsublimation  of  pure  hydrastinine  hydrochloride.  D,  Crystals  of 
hydrastine  formed  upon  the  addition  of  water  to  the  amorphous  and  crystalline  sublimate 
obtained  in  the  heating  of  powdered  hydrastis.  E,  Resublimed  crystals  of  hydrastin 
obtained  from  the  chloroformic  solution  of  the  microsublimate. — After  Tunmann  in  Gehe 
fe  Co.'s  Handelsbericht,  1912. 

cum,  jalapa,  coca,  stramonium,  kamala,  cousso,  aurantii  fructus 
cortex,  guarana,  cacao,  kola,  cantharides,  podophyllum,  radix 
canaigre,  and  kava-kava.  (Consult  Figs.  101  to  104.) 


176 


A  TEXT-BOOK  OF  BOTANY. 


The  drugs  thus  far  studied  may  to  some  extent  be  grouped 
according  to  the  sublimable  constituents  which  give  characteristic 
reactions.  I.  Thein-  or  caffeine-containing  drugs,  as  coffee,  tea, 
cacao,  and  guarana.  2.  Arbutin-containing  drugs  or  those  yielding 
hydrochinon,  as  uva-ursi  and  other  Ericaceae.  3.  Drugs  yielding 
oxymethylanthraquinone  and  giving  a  distinct  purple  color  with 
solutions  of  the  alkalies,  as  rhamnus  purshianus,  frangula,  rheum, 
senna,  etc. 


FIG.  103.  Alkaloids  of  ipecac  obtained  by  sublimation  as  follows:  0.050  Gm.  of  the 
powdered  drug  is  mixed  with  2  drops  of  water  on  a  glass. slide  and  heated;  the  third  dis- 
tillate at  a  temperature  of  100°  to  115°  C.  gives  colorless  or  yellowish,  highly  refractive 
globules  (A)  in  which  crystals  of  emetin  separate.  B ,  Short,  rod-shaped  crystals  of  the  double 
salts  formed  on  the  addition  of  gold  chloride  to  the  globules  of  the  oily  distillate.  C,  Oily 
globules  of  the  distillate  uniting  and  in  which,  upon  the  addition  of  potassium  bismuth 
iodide,  small  spherites  arise.  D,  Crystals  of  the  alkaloids  formed  on  treating  small  sections 
of  ipecac  or  o.ooi  Gm.  of  the  powder  with  an  aqueous  solution  of  picric  acid  acidified  with 
hydrochloric  acid.  E,  Crystals  formed  at  edge  of  cover  glass. — After  Tunmann  in  Gehe  & 
Co.'s  Handelsbericht,  1912. 

Cell-sap  Colors. — The  majority  of  the  other  color-substances 
found  in  the  higher  plants  besides  the  green  and  yellow  principles 
previously  mentioned  occur  in  solution  in  the  cell-sap,  and  may 
be  in  the  nature  of  secondary  substances  derived  from  the  plastid 
pigments,  or  they  may  be  produced  directly  by  the  protoplasm. 
Upon  making  sections  of  the  tissues  containing  cell-sap  color- 
substances,  not  infrequently  strikingly  contrasting  colors  are 
observed  in  contiguous  cells;  as  in  the  petals  of  the  poppy  and 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       177 

petals  of  certain  lilies,  where  we  find  some  cells  of  a  deep  purple 
color,  others  of  a  deep  red,  and  still  others  of  intermediate  shades. 
These  substances  are  easily  extracted  with  water  or  dilute  alco- 
hol and  are  all  more  or  less  affected  by  certain  chemicals  (many 
of  which  occur  naturally  in  the  plant),  such  as  citric  acid,  oxalic 
acid,  salts  of  calcium,  iron,  aluminum,  etc. 


FIG.  104.  Microcrystals  formed  in  Kava-kava,  the  root  of  Piper  methysticum:  A, 
crystals  of  methysticin  obtained  on  treatment  of  sections  of  the  root  or  the  powder  with 
alcohol,  the  crystals  being  long  rods,  of  a  light  yellow  color,  attaining  a  length  of  0.160  mm. 
and  becoming  of  a  violet  red  on  the  addition  of  sulphuric  acid.  B,  Crystals  of  methysti- 
cinic  acid  obtained  upon  heating  a  small  quantity  of  the  powder  with  one  or  two  drops 
of  a  solution  of  potassium  hydroxide,  then  adding  dilute  alcohol  and  allowing  the  slide  to 
stand  for  24  hours.  Crystals  of  methysticin  can  also  be  obtained  upon  sublimation,  pro- 
viding the  powder  has  been  acted  on  previously  with  dilute  sulphuric  acid,  emulsin,  or 
saliva. — After  Tunmann  in  Gehe  &  Co.'s  Handelsbericht,  1912. 

A  number  of  plant  pigments  of  this  class  are  used  as  indi- 
cators in  volumetric  chemical  analysis,  their  use  in  this  connection 
being  dependent  upon  their  sensitiveness  to  acids  and  alkalies. 
The  fact  that  they  respond  to  iron  salts, — that  is,  give  a  blue  or 
green  reaction  with  these  salts, — would  indicate  that  they  are 
associated  with  tannin  or  that  they  are  tannin-like  compounds,  as 
has  been  supposed  by  some  writers,  but  they  behave  very  differ- 

12 


178  A  TEXT-BOOK  OF  BOTANY. 

ently  from  tannin  toward  other  reagents,  such  as  organic  acids, 
alkalies,  lime  water,  and  solution  of  alum. 

An  examination  of  the  color-substances  of  a  large  number  of 
plants  shows  that  the  flower  color-substances  are  distributed  in 
all  parts  of  the  plant.  For  example,  the  flower  color-substance  of 
the  rose  occurs  in  the  leaves  and  prickles  as  well  as  in  the  petals. 

The  color-substance  in  the  root  of  the  radish  closely  corre- 
sponds to  that  in  the  flowers,  while  the  one  in  the  grains  of  black 
Mexican  corn  corresponds  to  that  in  corn  silk. 

The  cell-sap  color-substances  are  usually  found  in  greatest 
amount  at  the  tips  of  the  branches,  this  being  well  marked  in  the 
foliage  of  the  rose,  and  may  be  said  to  be  rather  characteristic 
of  spring  foliage.  Not  infrequently  in  the  purple  beech  the  young 
leaves  will  be  of  a  distinct  purplish-red  color  and  almost  entirely 
free  from  chlorophyll,  suggesting  a  correspondence  in  position 
and  color  to  a  flower. 

Color  in  Autumn  Leaves. — The  coloring  matters  in  both 
spring  and  autumn  leaves  closely  resemble  the  cell-sap  color- 
substances  of  flowers,  although  it  is  the  spring  leaves  which  give 
the  most  satisfactory  results  when  examined.  The  fact  that  in 
the  autumn  leaves  there  is  little  or  none  of  the  plastid  pigment 
present  would  point  to  the  conclusion  that  the  color-substances 
occurring  in  these  leaves  are  in  the  nature  of  by-products  and  of 
no  further  use  to  the  plant.  Of  course,  in  the  case  of  autumn 
leaves,  we  know  that  these  products  cannot  be  further  utilized 
by  the  plant,  and  for  this  reason  we  are  justified  in  regarding 
them  as  waste  products. 

So-called  White  Colors. — The  so-called  white  colors  in  plants 
do  not  properly  belong  to  either  class,  but  may  be  said  to  be 
appearances  due  rather  to  the  absence  of  color,  and  depending 
upon  the  reflection  of  light  from  transparent  cells  separated  by 
relatively  large  intercellular  spaces  containing  air.  In  other  words, 
the  effect  produced  by  these  cells  may  be  likened  to  that  produced 
by  the  globules  in  an  emulsion.  The  white  appearance  is  most 
pronounced  in  the  pith  cells  of  certain  stems,  where  on  the  death 
of  the  cells  the  size  of  the  intercellular  spaces  is  increased  and 
the  colorless  bodies  in  the  cells  as  well  as  the  walls  reflect  the 
light  like  snow  crystals. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       179 

CHEMISTRY  OF  PLANT  COLOR  PRINCIPLES. — The  substances 
giving  colors  in  plants  may  be  divided  into  two  classes:  i.  Sub- 
stances having  a  specific  color,  as  chlorophyll  in  leaves,-  chromo- 
phyll  in  flowers  and  fruits,  and  anthocyanin,  the  cell-sap  color 
in  flowers.  2.  Substances  which,  while  they  themselves  are  color- 
less and  known  as  leuco-compounds,  yet  form  color  derivatives. 
Some  of  these  are  more  or  less  readily  oxidized,  forming  charac- 
teristic color-substances,  as  brazilin.  Again,  some  occur  as  gluco- 
sides  which  through  the  action  of  ferments  yield  color-substances, 
as  quercitrin,  which  yields  the  yellow  pigment  quercetin.  All  of 
the  researches  which  have  been  made  seem  to  indicate  that  the 
color  in  plants  is  due  to  a  basic  substance  or  nucleus,  and  that 
the  variation  in  color  is  due  to  the  nature  and  arrangement  of 
certain  groups  and  side  chains.  For  example,  benzo-quinhydrone 
is  green  in  color,  while  thymo-quinhydrone  is  of  a  purplish  color 
(Pharm.  Review,  1908,  p.  330) .  Again,  the  hydroxybenzoquinones 
vary  in  color  with  the  number  of  hydroxy  groups,  hydroxybenzo- 
quinone  being  of  a  light  yellow,  di-hydroxybenzoquinone  is  of  a 
dark  yellow,  tri-hydroxybenzoquinone  is  of  a  black  color,  and 
tetra-hydroxybenzoquinone  is  of  a  bluish-black  color. 

In  the  artificial  dyes  there  are  a  number  of  so-called  chromo- 
phores  or  chromophorous  groups  (radicals)  characteristic  of  the 
various  classes.  In  plant  color-substances,  on  the  other  hand,  we 
find  the  carbonyl  group  (C  =  O),  the  imido  group  (NH),  and 
C  =  C  group.  The  introduction  of  the  chromophorous  radical 
gives  a  basic  compound  which  is  more  or  less  colored  and  known 
as  a  chromogen.  The  intensity  of  the  color  varies  on  the  intro- 
duction of  certain  salt-producing  groups  or  auxochromes.  In 
the  case  of  plant  pigments,  the  most  important  of  these  is  the 
hydroxyl  group,  and,  as  we  have  just  seen,  the  intensity  of  color 
varies  according  to  the  number  of  these  groups. 

According  to  their  constitution,  plant  color  principles  may  be 
arranged  into  six  different  classes:  i.  Phenol  derivatives,  includ- 
ing oTcin,  the  coloring  principle  in  many  lichens,  that  forms  color- 
less prisms  which  become  red ;  and  thymo-quinone  found  in 
Monarda  (Kremers,  in  Pharm.  Rev.,  1908,  p.  329).  2.  Naphtha- 
lene derivatives,  including  juglon,  which  forms  garnet-colored 
needles.  3.  Anthracene  derivatives,  including  alizarin,  the  color- 


180  A  TEXT-BOOK  OF  BOTANY. 

ing  principle  in  madder  root.  4.  Pyrone  derivatives,  of  which 
there  are  several,  as  gentisein,  maclurin,  catechin,  and  rottlerin. 
being  xanthone  derivatives ;  quercetin,  rhannetin,  and  fisetin,  which 
are  flovone  derivatives ;  and  hsematoxylin  and  brasilin,  being  chro- 
mene  derivatives.  5.  Isoquinoline,  of  which  berberine  is  an  ex- 
ample. 6.  Benz-pyrrol  derivatives ;  in  this  group  is  indigotin  or 
indigo  blue,  the  coloring  principle  in  Indigofera  tinctoria>. 

ORIGIN  AND  FORMATION  OF  ANTHOCYANIN. — At  the  present 
time  it  is  very  difficult  to  determine  the  nature  of  the  chemical 
processes  which  underlie  the  formation  of  anthocyanin,  or  the 
pigment  dissolved  in  the  cell-sap  and  giving  the  blue,  purplish,  and 
reddish  color  to  flowers,  fruits,  etc.  A  great  many  observations 
have  been  made  on  the  distribution  of  anthocyanin,  the  nature 
of  the  constituents  with  which  it  is  associated  in  the  plant  cell, 
and  their  relation  to  various  metabolic  processes.  In  order  to 
determine  the  Mendelian  factors  for  color  it  is  necessary  that 
we  have  a  definite  knowledge  concerning  the  nature  and  formation 
of  this  pigment.  Of  the  numerous  theories  which  have  been 
proposed  concerning  the  formation  of  anthocyanin,  that  proposed 
by  Muriel  Wheldale  (Jour.  Genetics,  1911,  p.  134)  seems  the  most 
plausible  and  is  as  follows: 

(1)  The   soluble  pigments   of   flowering  plants,   collectively 
termed  anthocyanin,  are  oxidation  products  of  colorless  chromo- 
gens  of  an  aromatic  nature,  which  are  present  in  the  living  tissues 
in  combination  with  sugar  as  glucosides. 

(2)  The  process  of  formation  of  the  glucoside  from  chromo- 
gen  and  sugar  is  of  the  nature  of  a  reversible  enzyme  action : 

Chromogen  +  sugar  "^""^  glucoside  +  water. 

(3)  The  chromogen  can  only  be  oxidized  to  anthocyanin  after 
liberation   from  the  glucoside,  and  the  process  of  oxidation  is 
carried  out  by  one  or  more  oxidizing  enzymes : 

Chromogen  +  oxygen  =  anthocyanin. 

(4)  From  (2)  and  (3)  we  may  deduce  that  the  amount  of  free 
chromogen,  and  hence  the  quantity  of  pigment  formed  at  any 
time  in  a  tissue,  is  inversely  proportional  to  the  concentration 
of  the  sugar  and  directly  proportional  to  the  concentration  of 
glucoside  in  that  tissue. 

(5)  The  local  formation  of  anthocyanin,  which  is  character- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       181 

istic  of  the  normal  plant,  is  due  to  local  variation  in  concentration 
of  either  the  free  sugars  or  the  glucosides  in  the  tissues  in  which 
the  pigment  appears.  The  abnormal  formation  of  pigment  under 
altered  conditions  is  due  to  differences  in  the  concentration  of 
these  same  substances  due  to  changes  in  metabolism  brought  about 
by  these  conditions. 

(6)  On  the  above  hypothesis  the  formation  of  anthocyanin  is 
brought  into  line  with  that  of  other  pigments  produced  after  the 
death  of  the  plant,  as,  for  example,  indigo  and  the  post-mortem  or 
respiration  pigments,  so  termed  by  Palladin. 

FUNCTION  OF  PLANT  COLORS. — A  great  many  theories  have 
been  advanced  as  to  the  nature  and  uses  of  color-substances  by 
the  plant.  With  the  exception  of  chlorophyll  present  in  the  chloro- 
plastid  and  its  relation  to  photosynthetic  processes  little  is  known 
concerning  the  other  pigments.  Without  attempting  to  discuss  the 
various  theories  which  have  been  proposed  concerning  their  uses, 
the  following  facts  should  be  borne  in  mind : 

1.  The  occurrence  of  chromoplastids  in  a  reserve  organ,  as  in 
the  tuberous  root  of  carrot,  and  the  similar  occurrence  of  chromo- 
plastids and  of  reserve  starch  in  the  petals  of  the  buttercup,  lead 
to  the  inference  that  the  petal  of  the  buttercup,  like  the  root  of  the 
carrot,  has  the  function  of  storing  nutrient  material.    In  each  case 
cells  containing  chromoplastids  rich  in  nitrogenous  substances  are 
associated  with  cells  containing  reserve  materials. 

2.  The  distribution  of  the  so-called  flower  color-substances  in 
other  parts  of  the  plant  than  the  flower  shows  them  to  be  in  the 
nature  of  metabolic  substances,  and  that  the  part  which  they  play 
in  attracting  insects  to  flowers  is  incidental  rather  than  funda- 
mental.    (The  fact  that  certain  colored  flowers  as  in  spruce  are 
pollinated  by  the  wind  would  tend  to  confirm  this  view.) 

3.  Unorganized  or  cell-sap  color-substances   are   distributed 
usually  in  largest  amount  at  the  termini  of  the  branches,  as  in 
flowers  and  terminal  leaves,  or  in  roots,  or  in  both  tops  and  roots. 
Their  occurrence  in  those  portions  of  the  plant  which  are  young 
and  growing  points  to  the  conclusion  that  they  are  not  to  be  disre- 
garded in  the  study  of   metabolic  processes.     Goebel   likewise 
holds  to  this  view.     He  says  that  it  is  "  very  probable  that  the 


182  A  TEXT-BOOK  OF  BOTANY. 

feature  of  color  which  so  often  appears  when  the  propagative 
organs  are  being  brought  forth  has  some  connection  with  definite 
metabolic  processes,  although  up  till  now  we  cannot  recognize 
what  these  are." 

ARTIFICIAL  COLORING  OF  FLOWERS. — Ever  since  the  time  of 
Magnol  (1709)  there  has  been  considerable  interest  in  the  subject 
of  coloring  white  flowers.  A  number  of  aniline  dyes  can  be  used, 
but  those  belonging  chiefly  to  the  azo  and  rosaniline  coloring 
matters,  especially  the  acid  dyes  or  those  used  for  dyeing  wool, 
give  the  best  result.  These  dyes  are  readily  soluble  in  water,  and 
the  solutions  are  made  up  of  a  strength  of  I  part  of  dye  to  1,000 
parts  of  water.  The  effects  are  best  seen  in  white  flowers  and 
are  produced  by  allowing  the  flower-stalks  to  remain  in  the  solu- 
tions from  one  to  two  hours,  when  they  are  placed  in  water. 
With  some  flowers,  as  the  cultivated  anemones,  the  effects  are 
noticeable  in  from  ten  to  fifteen  minutes.  Some  flowers  will  take 
up  the  dyes  better  than  others.  White  flowers  may  be  changed 
to  yellow,  orange,  blue,  green,  purplish-red  or  magenta,  crimson, 
purple,  salmon-pink  or  gray  by  the  use  of  the  following  dyes: 

1.  Yellow  flowers  are  produced  by  the  use  of  the  dye  known 
commercially  as  "  Acid  Yellow  A.  T.,"  which  is  chemically  the 
sodium  salt  of  disulpho-diphenylazin-dioxytartaric  acid. 

2.  Orange-colored  flowers  may  be  produced  by  the  use  of  the 
Jdye  "  Orange  G.  G.,"  which  is  the  sodium  salt  of  benzene-azo-/?- 
'naphthol-disulphonic  acid. 

3.  Blue   flowers   may   be  produced   by   the   use   of   the   dye 
"  Cyanol  F.  F.,"  which  is  the  sodium  salt  of  meta-oxy-diethyl- 
diamido-phenyl-ditolyl-carbinol-disulphonic  acid. 

4.  Green  flowers  may  be  produced  by  the  use  of  equal  parts 
of  the  dyes  "  Acid  Yellow  A.  T.,"  and  "  Cyanol  F.  F." 

5.  Purplish-red  flowers  are  produced  by  the  use  of  the  dye 
"  Acid  Magenta,"  which  is  the  sodium  salt  of  the  trisulphonic 
acid  of  rosaniline. 

6.  Crimson  flowers  may  be  produced  by  the  use  of  equal  parts 
of  the  dyes  "  Acid  Yellow  A.  T."  and  "  Acid  Magenta." 

7.  Purple  flowers  may  be  produced  by  the  use  of  equal  parts 
of  "  Cyanol  F.  F."  and  "  Acid  Magenta." 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       183 

8.  Salmon-pink  flowers  may  be  produced  by  the  use  of  the  dye 
"  Brilliant  Croceine  M.  O.  O.,"  which  is  the  sodium  salt  of  ben- 
zene-azo-benzene-azo-/?-naphthol-disulphonic  acid. 

9.  Gray  flowers  may  be  produced  by  the  use  of  the  dye  "  Naph- 
thol  Black  B.,"  which  is  the  sodium  salt  of  disulpho-/?-naphtha- 
lene-azo-  «-naphthalene-azo-/?-naphthol-disulphonic  acid. 

Calcium  oxalate  is  found  in  many  of  the  higher  plants,  and 
in  the  algae  and  fungi  as  well ;  while  in  the  mosses,  ferns,  grasses, 
and  sedges  it  is  seldom  found.  It  occurs  in  plants  in  crystals  of 
either  the  monoclinic  or  tetragonal  system.  The  crystals  dissolve 
in  any  of  the  mineral  acids  without  effervescence,  and  their  identity 
is  usually  confirmed  by  the  use  of  dilute  hydrochloric  acid.  The 
crystals  of  the  monoclinic  system  are  rather  widely  distributed, 
while  those  of  the  tetragonal  system  are  less  frequent  in  their 
occurrence. 

The  crystals  belonging  to  the  monoclinic  system  (Fig.  105) 
may  be  subdivided  according  to  their  prevalent  forms  into  a  num- 
ber of  sub-groups. 

I.  SOLITARY  CRYSTALS. — These  are  usually  in  the   form  of 
rhombohedra,  sometimes  in  twin  crystals  of  variable  size   (Fig. 
108).    They  are  very  widely  distributed,  occurring  in  a  number  of 
modifications  in  the  same  plant,  and  are  often  very  characteristic  in 
the  identification  of  economic  products.    The  crystals  of  this  group 
are  sometimes  mistaken  for  silica,  owing  to  the  fact  that  in  some 
instances  the  lumen  of  the  cell  is  completely  filled  by  the  crystal, 
and,  the  inner  wall  having  the  contour  of  the  crystal,  it  is  impossible 
to  determine  whether  the  crystal  is  affected  by  the  use  of  hydro- 
chloric acid.     It  should  be  stated  in  this  connection  that  silica 
never  occurs  as  a  cell-content  in  sharp,  angular  crystals,  but  either 
in  more  or  less  ellipsoidal  or  irregular  hollow  masses,  or  in  some- 
what solid,  irregularly  branching  forms  (Fig.  109). 

II.  COLUMNAR  CRYSTALS  or  "  styloids,"  being  elongated  prisms 
of  the  monoclinic  system  (Fig.  107,  C),  and  when  typical  recall 
ihe  crystals  of  gypsum.     They  also  occur  in  twin-forms,  some- 
limes  replacing  raphides,   and   occasionally   show   a  number  of 
transition  forms. 

Solitary  crystals  in  the  form  of  rhombohedra  or  styloids  occur 
in  a  number  of  drugs,  as  follows :  Acer  spicatum,  calumba,  carda- 


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A  TEXT-BOOK  OF  BOTANY. 


PIG.  105.  Monoclinic  crystals  of  calcium  oxalate:  A,  a  to  f,  crystals  from  the  paren- 
chyma of  the  bark  of  the  horse-chestnut  (ALsculus  Hippocastanum);  B,  a  to  c,  from  the  pith 
of  Periploca  grceca;  C,  a  to  e,  from  the  parenchyma  in  the  region  of  the  fibrovascular  bundles 
in  Musa  sinensis;  D.  a  to  c,  from  the  petioles  of  the  pinnate  leaves  of  Cycas  revoluta;  E,  a  to 
c,  crystals  from  the  bark  of  the  guaiac  tree;  F,  a  single  crystal  from  Citrus  aurantium;  G, 
a  to  c,  rectangular  crystals  from  a  Brazilian  bignonia. — After  Dippel  in  "Das  Mikroskop." 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       185 

momum,  coca,  eucalyptus,  frangula,  gelsemium,  granatum,  hama- 
melis,  hyoscyamus,  Jamaica  quassia,  krameria,  pimenta,  Prunus 
serotina,  quercus,  quillaja,  rhamnus  purshianus,  senna,  uva-ursi, 
vanilla,  viburnum  prunifolium,  and  xanthoxylum. 

III.  ROSETTE  AGGREGATES  of  calcium  oxalate  consist  of  numer- 
ous small  prisms  and  pyramids,  or  hemihedral  crystals  more  or 
less  regularly  arranged  around  a  central  axis,  and  have  the  appear- 


FIG.  1 06.  Orthorhombic  crystals  of  calcium  oxalate:  A,  a  to  f,  crystals  from  the  leaves 
of  the  onion  (Allium  Cepa)\  B,  a  to  g,  crystals  from  the  stem  of  Tradescantiaviridis. — After 
Dippel  in  "Das  Mikroskop." 

ance  of  a  rosette  or  star  (Fig.  107,  A).  The  development  of 
these  aggregates  may  be  readily  observed  in  the  'stem  of  Datura 
Stramonium.  Crystals  of  this  class  are  more  widely  distributed 
than  any  of  the  others,  and  are  characteristic  of  a  number  of  drugs. 
Clustered  crystals  in  the  form  of  rosette  aggregates  occur  in 
numerous  drugs,  as  follows:  Althaea,  anisum,  buchu,  calendula, 
cannabis  indica,  carum,  caryophyllus,  castanea,  chimaphila,  conium, 
coriandrum,  cusso,  eriodictyon,  euonymus,  fceniculum,  frangula, 
galla,  geranium,  gossypii  cortex,  granatum,  humulus,  jalapa,  pilo- 


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A  TEXT-BOOK  OF  BOTANY. 


carpus,  pimenta,  rheum,  rumex,  senna,  stillingia,  stramonii  folia, 
viburnum  opulus,  and  viburnum  prunifolium. 

IV.  RAPHIDES  are  groups  of  needle-shaped  crystals,  especially 
prevalent  in  Monocotyledons  (Fig.  107,  B).    They  have  been  mis- 


FIG.  107.  Forms  of  calcium  oxalate  crystals:  A,  transverse  section  of  rheum  show- 
ing rosette  aggregates  of  calcium  oxalate  in  three  of  the  cells  and  starch  grains  in  some  of 
the  others;  B,  longitudinal  section  of  scilla  showing  raphides;  C,  longitudinal  section  of 
quillaja  showing  large  monoclinic  prisms  of  calcium  oxalate  and  also  some  starch  grains; 
D,  transverse  section  of  belladonna  root  showing  one  cell  filled  with  sphenoidal  micro-crys- 
tals, the  remaining  cells  containing  starch. 

taken  by  several  observers  for  calcium  phosphate.  Calcium  phos- 
phate, however,  occurs  in  plants  either  in  solution  or  in  com- 
bination with  protein  substance.  The  cells  containing  raphides 
are  long,  thin-walled  and  contain,  sooner  or  later,  a  mucilage, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       187 


which  arises  from  the  cell-sap,  is  stained  by  corallin,  and  behaves 
with  reagents  much  like  cherry-gum.  The  cells  are  either  isolated 
or  occur  in  groups  placed  end  to  end,  as  in  Veratrum  viride. 

Raphides  are  found  in  relatively  few  drugs,  as  follows : 
Cinnamomum,  convallaria,  cypripedium,  ipecacuanha,  phytolacca, 
sarsaparilla,  scilla,  vanilla,  and  veratrum  viride. 

V.  CRYSTAL  FIBERS. — In  quite  a  number  of  drugs  a  single 
monoclinic  prism  or  a  rosette  aggregate  occurs  in  each  of  the 
parenchyma  cells  adjoining  the  sclerenchymatous  fibers,  and  to 
this  single  longitudinal  row  of  superimposed  cells  the  name  crystal 


FIG.  1 08.  A,  transverse  section  of  hyoscyamus  leaf  showing  monoclinic  prisms  of 
calcium  oxalate,  also  a  twin-crystal;  B,  longitudinal  section  of  glycyrrhiza  showing  a 
crystal  fiber,  i.e.,  a  row  of  superimposed  cells,  each  containing  a  polygonal  monoclinic 
prism  of  calcium  oxalate,  the  crystal  filling  the  cell.  Adjoining  the  crystal  fiber  is  a  group 
of  bast  fibers  on  one  side  and  some  cells  containing  starch  on  the  other. 

fiber  has  been  applied  (Fig.  108,  B).  Crystal  fibers  are  typical 
of  the  following  drugs:  Aspidosperma,  frangula,  glycyrrhiza, 
hsematoxylon,  hamamelis,  Prunus  serotina,  quercus  alba,  quil- 
laja,  rhamnus  purshianus,  and  uva-ursi. 

VI.  MICRO-CRYSTALS  are  exceedingly  small  (about  0.2  to  lo/* 
in  diameter),  apparently  deltoid  or  arrow-shaped,  and  so  numerous 
as  to  entirely  fill  the  parenchyma  cells  in  which  they  occur,  giving 
the  cells  a  grayish-black  appearance  which  readily  distinguishes 
them  from  other  plant  cells  (Fig.  107,  D).  It  has  been  sup- 
posed that  they  are  tetrahedrons,  but  they  are  probably  sphenoids 


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A  TEXT-BOOK  OF  BOTANY. 


in  the  monoclinic  system,  inasmuch  as  monoclinic  prisms  occur  in 
neighboring  cells  in  the  same  plant  or  drug,  as  in  stramonium, 
quassia,  etc.  Because  they  are  so  small  and  in  many  instances 
not  clearly  defined  they  have  been  termed  by  the  Germans  "  crystal- 


FIG.  109.  Various  forms  of  Silica  found  in  plants.  Long  rods  and  spindle-shaped 
masses  (A)  and  star-shaped  fragments  (B)  found  respectively  in  the  thalloid  structure 
made  up  of  roots  and  shoots  and  in  the  leaves  of  Tristicha  hypnoides,  a  small,  moss-like 
plant  (Podostemaceae)  growing  on  rocks,  etc.,  in  running  water,  especially  in  waterfalls. 
C,  a  longitudinal  section  of  the  petiole  of  Caryota  urens,  a  palm  of  Eastern  Asia,  showing 
grape-like  clusters  of  silica  completely  filling  the  cells.  D,  hat-shaped  fragments  of  silica 
occurring  on  the  edge  of  the  leaves  of  Cusparia  macrophylla.  a  rutaceous  tree  growing  near 
Rio  Janeiro;  in  a,  b,  c,  side  views  of  the  masses,  whereas  in  d  the  surface  view  shows  a  struc- 
ture resembling  that  of  sphero-crystals,  E  and  F,  siliceous  fragments  from  the  leaves  of  an 
orchid,  Oncidium  leucochilum,  growing  in  Guatemala;  in  E  is  shown  a  base  fiber  with  siliceous 
masses  somewhat  resembling  the  crystal-fibers  of  calcium  oxalate,  and  in  F  the  isolated 
siliceous  masses  are  seen. — A  and  B,  after  Cario;  C  and  D,  after  Rosanoff;  E  and  F,  after 
Pfitzer. — From  Dippel  in  "Das  Mikroskop." 

sand"  (Kristallsand).    The  typical  tetrahedral  form  was  recog- 
nized by  the  French  and  termed  "  sable  tetraedrique." 

Sphenoidal  micro-crystals  are  found  in  the  following  drugs : 
Belladonnae  folia,  belladonnse  radix,  cinchona,  dulcamara,  phyto- 
lacca,  quassia,  Solanum  carolinense,  and  tabacum. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       189 

VII.  MEMBRANE  CRYSTALS. — There  are  several  forms  of 
crystals  which  may  be  included  in  this  group.  The  so-called 
Rosanoff  crystals  consist  of  rosette  aggregates  attached  to  inward- 
protruding  walls  of  the  plant  cell.  These,  however,  do  not  concern 
us  so  much  as  the  large  monoclinic  crystals  which  have  a  mem- 
brane surrounding  them.  The  crystal  first  appears  in  the  cell-sap, 
and  then  numerous  oil  globules  appear  in  the  protoplasm  around 
it;  later  some  of  the  walls  of  the  cell  thicken  and  grow  around 
the  crystal,  which  they  finally  completely  envelop,  as  in  Moracese. 

Crystals  of  the  orthorhombic  system  may  occur  either  as  soli- 
tary crystals  or  rosette  aggregates,  or  in  the  form  of  acicular 
crystals  and  probably  micro-crystals,  being  usually  much  smaller 
than  the  single  crystals  of  the  monoclinic  system. 

Solereder,  in  his  work  on  "  Systematic  Anatomy  of  the  Dicoty- 
ledons," states  that  the  systematic  value  of  the  study  of  the  forms  of 
crystals  varies  considerably.  While  in  some  instances  a  certain 
form  of  crystal  is  characteristic  of  an  entire  order,  yet  in  other 
cases  it  serves  to  distinguish  only  genera  or  species.  In  practical 
work  in  the  identification  of  economic  products  the  study  of  the 
forms  of  crystals  is  very  important.  A  few  instances  may  be 
mentioned.  In  Jamaica  quassia  calcium  oxalate  occurs  in  the 
form  of  4-  to  6-sided  rhombohedral  crystals,  whereas  in  Surinam 
quassia  the  crystals  are  few  or  entirely  wanting.  In  Levant 
scammony  root  occur  numerous  monoclinic  prisms  of  calcium  oxa-l 
late,  whereas  in  the  Mexican  root  the  crystals  are  chiefly  in  the 
form  of  rosette  aggregates.  In  the  bark  of  Viburnum  Opulus  the 
calcium  oxalate  occurs  almost  entirely  in  the  form  of  rosette  aggre- 
gates, whereas  in  the  bark  of  Acer  spicatum  solitary  rhombo- 
hedral crystals  are  prevalent.  In  the  identification  of  many 
drugs  the  presence  or  absence  of  calcium  oxalate  crystals  and 
the  study  of  the  prevalent  forms  is  very  important  (Fig.  no). 

Owing  to  the  importance  of  the  study  of  calcium  oxalate  an 
enumeration  of  the  families  in  which  calcium  oxalate  occurs  is 
given. 

I.  Crystals  of  calcium  oxalate,  either  in  the  form  of  solitary 
rhombohedra  or  clustered  aggregates,  are  found  in  the  following* 
families:  Aceracese,  Ampelidacese  (also  raphides),  Anacardiaceae, 
Apocynacese,  Araliacese,  Asclepiadaceae,  Berberidaceae,  Bignonia- 


190 


A  TEXT-BOOK  OF  BOTANY. 

A  B 


FIG.  no.  A  few  illustrations  showing  the  practical  value  of  the  study  of  calcium 
oxalate:  A,  digitalis,  without  any  calcium  oxalate;  B,  hyoscyamus  in  which  monoclinic 
prisms  predominate;  C,  belladonna,  characterized  chiefly  by  sphenoidal  micro-crystals  as 
well  as  occasional  prisms;  D,  stramonium,  having  rosette  aggregates  in  addition  to  prisms 
which  are  found  in  the  petioles  and  stems  and  sphenoidal  micro-crystals,  which  are  abundant 
in  the  root. — a,  upper  epidermis;  b,  lower  epidermis;  c,  non-glandular  hairs  (which  in  stra- 
monium art  tubercutete) ;  d,  glandular  hairs;  e,  calcium  oxalate  crystals;  f,  fragments  of 
xylem  showing  tracheae  with  bordered  pores  (s),  reticulate  markings  (r),  simple  pores  (p), 
spiral  thickening  (1),  and  wood  fibers  (w);  g,  bast  fibers,  which,  together  with  wood  fibers, 
are  wanting  in  digitalis. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       191 

ceae  (also  in  the  form  of  octahedra  and  small  acicular  crystals), 
Bixaceae,  Bruniaceae,  Burseraceae,  Buxaceae  (also  styloids  and 
micro-crystals),  Cactaceae,  Canellaceae,  Capparidaceae,  Caprifolia- 
ceae,  Caryophyllaceae,  Casuarinaceae,  Celastraceae,  Combretaceae, 
Convolvulaceae  (also  small  acicular  crystals),  Cornaceae  (also 
micro-crystals),  Ebenaceae,  Ericaceae,  Euphorbiaceae,  Fagaceae, 
Geraniaceae  (also  raphides),  Gutti ferae,  Hamamelidaceae,  Hippo- 
castanaceae,  Hypericaceae,  Juglandaceae,  Lecythidaceae,  Linaceae, 
Loganiaceae,  Loranthaceae,  Lythraceae;  Magnoliaceae,  Malpighia- 
ceae,  Malvaceae,  Meliaceae,  Menispermaceae  (also  small  acicular 
crystals),  Moraceae,  Myricaceae,  Myrsinaceae,  Myrtaceae,  Oleaceae, 
Passifloraceae,  Pittosporaceae  (also  columnar  crystals),  Platana- 
ceae,  Plumbaginaceae,  Podostemaceae,  Polygalaceae,  Polygonaceae, 
Portulacaceae  (also  micro-crystals),  Rhamnaceae,  Rhizophoraceae, 
Rosaceae,  Rubiaceae  (also  raphides,  micro-crystals,  rhombohedra, 
and  small  acicular  crystals),  Rutaceae  (also  styloids  and  raphides), 
Salicaceae,  Santalaceae,  Sapindaceae,  Sapotaceae  (also  micro-crys- 
tals), Saxifragaceae,  Simarubaceae,  Solanaceae  (also  micro-crys- 
tals), Staphyleaceae,  Sterculiaceae,  Theaceae  (also^  raphides  and 
styloids),  Thymelaeaceae  (also  micro-crystals),  Tiliaceae,  Ulmaceae, 
Urnbelliferae,  Urticaceae,  Vaccinaceae,  Verbenaceae  (also  small 
prisms  and  acicular  crystals),  Violaceae,  and  Zygophyllaceae. 

Solitary  rhombohedra  are  found  in  a  relatively  few  families 
and  are  characteristic  of  the  following :  Connaraceae,  Crassulaceae, 
Cucurbitaceae,  and  Leguminosae. 

II.  Crystals  in  the  orthorhombic  system  occurring  in  the  form 
of  small  octahedra  or  prisms,  as  twin-crystals,  and  in  the  form  of 
short  rods  or  needles  are  found  in  the  following  families :  Acera- 
ceae,  Apocynaceae,  Araliaceae,  Aristolochiaceae,  Begoniaceae,  Big- 
noniaceae,  Boraginaceae,  Cactaceae,  Caesalpinaceae,  Calycanthaceae, 
Campanulaceae,  Canellaceae,  Capparidaceae,  Chenipodiaceae,  Com- 
positae,  Convolvulaceae,  Gentianaceae,  Gesneraceae,  Guttiferae,  Lau-' 
raceae,  Loganiaceae,  Magnoliaceae,  Melastomaceae,  Menispermaceae, 
Moraceae,  Myristicaceae,  Monimiaceae,  Oleaceae,  Papilionaceae, 
Phytolaccaceae,  Piperaceae,  Polemoniaceae,  Ranunculaceae,  Rubia- 
ceae, Saxifragaceae,  Scrophulariaceae,  Simarubaceae,  Solanaceae, 
Sterculiaceae,  Styracaceae,  and  Zygophyllaceae. 


192  A  TEXT-BOOK  OF  BOTANY. 

III.  Rosette  aggregates  or  clustered  crystals  sometimes  accom- 
panying other  forms  are  found  in  the  following  families  :  Acantha- 
ceae,  Begoniaceae,  Boraginaceae,  Calyceraceas,  Campanulaceae,  Can- 
dolleaceae,  Chenopodiaceae,  Chloranthaceae,  Elatinaceae,  Empetra- 
ceae,  Gentianaceae,  Gesneraceae,  Hydrophyllaceae,  Labiatae,  Loasa- 
ceae,   Magnoliaceae,   Melastomaceae,   Melianthaceae,   Myristicaceae, 
Nepenthaceae,  Nymphaeaceae,  Onagraceae,  Papaveraceae,  Phytolac- 
caceae,  Piperaceae,  Polemoniaceae,  Ranunculaceae,  Sarraceniaceae, 
and  Turneraceae. 

IV.  Sphaerites   (sphere-crystals),  or  rosette  aggregates  com- 
posed of  very  small  needles,  have  been  observed  in  certain  plants  of 
the  following  families:  Aceraceae,  Asclepiadaceae,  Berberidacese, 
Cactaceae,  Combretaceae,  Crassulaceae,  Empetraceae,  Euphorbiaceae, 
Geraniaceae,  Melastomaceae,  Papilionaceae,  Phytolaccaceae,  Rosa- 
ceae,  and  Solanaceae. 

V.  Raphides  are  sometimes  associated  with  other  forms  of 
crystals,  as  micro-crystals,  rosette  aggregates,  rhombohedra,  and 
styloids.    They  are  widely  distributed  among  the  Monocotyledons 
and  occur  in  the  following  Dicotyledons :  Geraniaceae,  Gesneraceae, 
Melianthaceae,  Phytolaccaceae,  Rubiaceae,  Rutaceae,  Saxifragaceae, 
Theaceae,  Urticaceae,  and  Zygophyllaceae. 

PLANT  PROTEINS. 

T^e  proteins  are  nitrogenous  compounds,  most  of  which  con- 
tain sulphur  and  some  of  which  contain  phosphorus.  Their  con- 
stitution or  the  molecular  structure  of  their  molecules  has  not 
been  determined,  but  they  are  very  large,  and  are  built  up  of  amino- 
acids,  the  simplest  of  which  is  glycocoll  (amino-acetic  acid). 

Apart  from  the  protoplasm  found  in  living  cells,  the  propor- 
tion of  proteins  in  plants  is  relatively  small,  except  in  seeds,  where 
they  serve  as  nutriment  during  the  germinating  period,  being  made 
available  by  the  action  of  proteolytic  enzymes.  Most  of  the  plant 
proteins  are  GLOBULINS,  and  collectively  have  been  termed  phyto- 
globulins.  (i)  The  globulins  are  insoluble  in  pure  water  and  in 
dilute  acids,  but  are  soluble  in  dilute  solutions  of  sodium  chloride 
(i  to  20  per  cent.),  ammonium  chloride,  sodium  sulphate  and 
dilute  solution  of  potassium  hydrate,  from  which  solutions  they 
may  be  precipitated  by  dilution,  dialysis,  or  acidification  with  CO2 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       193 

or  dilute  acids,  or  by  "  salting  out  "  by  the  use  of  strong  or  satu- 
rated solutions  of  ammonium  sulphate,  magnesium  sulphate,  or 
sodium  chloride.  (2)  The  proteins  which  contain  phosphorus  are 
sometimes  called  phytovitellins,  as  legumin  in  peas,  which  contain 
0.35  per  cent,  of  phosphorus.  A  third  class  of  plant  proteins, 
which  are  alcohol-soluble,  are  found  in  cereals,  as  the  gliadin 
of  wheat  and  rye  and  the  zein  of  maize.  The  cohesive  and  dough- 
ing  properties  of  wheat  flour  are  attributed  to  the  association  of 
gliadin  and  another  protein  called  glutenin. 

Some  of  the  plant  proteins  occur  naturally  in  the  crystalline 
form,  either  free  in  the  cytoplasm,  as  in  the  potato  tuber  (Fig.  in, 
A),  or  as  components  of  aleurone  grains,  as  in  the  seeds  of 
Ricinus  communif  and  Brazil  nuts  (Fig.  HI,  B  and  D).  Phyto- 
globulins  in  the  form  of  crystals  and  spheroids  have  been  obtained 
from  extracts  of  flax-seed,  hemp-seed,  Brazil-nut,  castor-oil  seeds 
and  others.  Protein  crystals  are,  according  to  Wichmann,  iso- 
morphic,  and  probably  belong  to  the  hexagonal  system  (Fig.  112). 

Aleurone  grains  are  made  up  of  phyto-globulins  (formerly 
called  crystalloids),  globoids  and  a  ground  mass,  the  whole  being 
enclosed  by  a  membrane-like  material.  They  may  be  studied  by 
taking  advantage  of  the  difference  in  solubility  of  the  substances 
composing  them.  The  membrane,  or  lining  of  the  protoplasm, 
while  soluble  in  water,  remains  intact  with  sections  examined  in 
any  of  the  fixed  oils,  as  cotton-seed  oil.  Usually  seeds  which 
contain  aleurone  are  rich  in  fixed  oils,  and  if  this  oil  is  first  removed 
by  placing  fresh  sections  in  alcohol,  or  alcohol  and  ether,  the 
subsequent  study  is  facilitated.  If  the  sections  thus  treated  are 
mounted  in  water,  the  membrane  gradually  dissolves,  leaving 
the  globulins,  globoids,  and  calcium  oxalate.  On  adding  a  o.i 
to  i  per  cent,  solution  of  either  sodium  or  potassium  hydrate,  the 
globulins  dissolve,  the  globoids  and  calcium  oxalate  crystals  re- 
maining unaffected.  The  globoids  may  be  dissolved  by  the  use 
of  a  i  per  cent,  acetic  acid  solution,  or  concentrated  solutions  of 
ammonium  sulphate  or  monopotassium  phosphate.  The  calcium 
oxalate  remaining  may  then  be  treated  with  hydrochloric  acid  in 
the  usual  way. 

CLASSIFICATION  OF  PROTEINS. — A  committee  on  protein  nomen- 
clature of  the  American  Society  of  Biological  Chemists  proposed 
13 


194 


A  TEXT-BOOK  OF  BOTANY. 


a  classification  of  Proteins  based  chiefly  on  their  solubility  under 
different  conditions.  There  are  some  eighteen  different  classes 
recognized,  and  these  are  brought  under  three  principal  groups: 
(i)  Simple  Proteins,  as  albumins,  globulins,  glutelins,  prolamins, 
etc.  (2)  Conjugated  Proteins,  or  complex  substances,  as  nucleo- 


FIG.  in.  Phyto-globulins:  A,  cell  of  tuber  of  white  potato  (Solanum  tuberosum) 
showing  protein  cyrstals  (k),  starch  grains  (st),  nucleus  (n);  B,  aleurone  grains  of  the 
seed  of  the  castor-oil  plant  (Ricinus  communis);  C.  aleurone  grains  of  fruit  of  fennel  (Fcenic- 
ulunt  vulgare)  containing  large  calcium  oxalate  crystals  (Ca)  which  are  strongly  polarizing, 
as  shown  in  the  isolated  grains;  D,  aleurone  grains  of  Brazil-nut  (Bertholletia  excelsa); 
g,  globoids;  k,  protein  crystals. 

proteins,  which  are  compounds  containing  both  nucleic  acid  and 
protein.  (3)  Derived  Proteins,  or  compounds  resulting  from  the 
action  of  enzymes  or  acids  upon  proteins. 

I.  Most  of  the  investigations  up  until  now  have  been  con- 
ducted on  the  Globulins,  which  are  distinguished  by  being  insoluble 
in  water  but  soluble  in  saline  solutions.  A  number  of  them  readily 
crystallize,  and  these  can  be  generally  obtained  by  diluting  their 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       195 

sodium  chloride  solutions  with  water  heated  from  50°  to  60°  until 
a  slight  turbidity  forms.  Warm  the  diluted  solution  until  the  tur- 
bidity disappears  and  then  allow  it  to  cool  slowly,  when  well- 
defined  crystals  of  the  protein  separate  (Fig.  112).  Crystals  of 
the  globulin  (so-called  excelsin)  of  Brazil-nut  were  obtained  by 
Osborne  by  simply  dialyzing  the  faintly  acid  saline  solution  in 
running  water.  Many  of  the  globulins  have  received  distinctive 
names,  as  Amandin,  found  in  the  almond,  peach,  plum,  and  apri- 
cot ;  Avenalin,  found  in  oats ;  Castanin,  found  in  European  chest- 
nut; Conglutin,  found  in  lupines;  Corylin,  found  in  hazel-nut; 
Edestin,  found  in  hemp-seed ;  Excelsin,  found  in  Brazil-nut ; 
Glycinin,  found  in  soy-bean;  Juglansin,  found  in  European  wal- 
nut, American  black  walnut,  and  butter-nut;  Legumin,  found  in 
peas  and  lentils ;  Maysin,  found  in  Indian  corn  or  maize ;  Phaseolin, 
found  in  kidney  and  lima  beans;  Tuberin,  found  in  the  potato; 
Vicilin,  found  in  peas,  horse-bean,  and  lentils ;  and  Vignin,  found 
in  cow-pea.  Globulins  have  also  been  isolated  from  the  seeds  of 
other  plants,  but  to  these  distinctive  names  have  not  yet  been 
given.  Among  these  may  be  mentioned  barley,  cocoanut,  castor- 
bean,  cotton-seed,  flaxseed,  mustard-seed,  peanut,  radish-seed, 
rape-seed,  rye,  sesame-seed,  sunflower-seed,  and  squash-seed. 

II.  ALBUMINS  are  distinguished  from  globulins  by  the  fact 
that  they  coagulate  on  the  application  of  heat ;  they  are  also  solu- 
ble in  water,  showing  neutral  or  but  a  slightly  acid  reaction.    Most 
seeds  and  probably  most  plant  juices  yield  proteins  which  are  as 
well  entitled  to  be  placed  in  the  group  of  albumins  as  any  of 
those  of  animal  origin.    The  best  characterized  vegetable  albumins 
are  Legumelin,  found  in  lentils,  cow-peas,  peas,  and  soy-beans ; 
Leucosin,  found  in  barley,  rye,  and  wheat;  Phaselin,  found  in 
kidney-bean;  and  Ricin,  found  in  castor-bean. 

III.  Another   well-defined   class   of    Proteins   are   known   as 
GLUTELINS,  which  are  characterized  by  being  insoluble  in  neutral 
aqueous  solutions,  saline  solutions,  and  alcohol.     The  glutenin  of 
wheat  is  the  best  representative  of  this  group. 

IV.  The  alcohol-soluble  proteins,  known  as  Prolamins,  have 
been  found  in  corn,  oats,  sorghum,  and  wheat.    It  has  recently  been 
proposed  to  bring  this  group  of  proteins  in  a  group  by  themselves 
and  call  them  "  gliadins,"  but  as  this  name  has  been  used  to 


196  A  TEXT-BOOK  OF  BOTANY. 

designate  a  definite  protein  obtained  from  wheat/a  more  distinctive 
name  has  been  proposed  by  Osborne,  who  calls  this  group  "  pro- 
lamins,"  because  all  its  members  which  have  thus  far  been  hydrol- 
yzed  yield  a  relatively  large  quantity  of  both  proline  and  amide 
nitrogen.  The  prolamins  are  characterized  by  their  solubility  in 
alcohol  from  70  to  90  per  cent.  They  are  nearly  or  wholly  insoluble 
in  water,  but  their  salts  are  freely  soluble  in  solutions  of  acids  or 
alkalies.  (See  "  The  Vegetable  Proteins/'  by  Thomas  B. 
Osborne.) 

GLUTEN  is  a  mixture  of  proteins  occurring  in  wheat.  It  con- 
sists of  about  4  per  cent,  of  gliadin  (prolamin)  and  4  per  cent,  of 
glutenin  (glutelin).  On  an  average  100  pounds  of  flour  will  yield 
8  pounds  of  gluten.  The  "  hard  "  wheats  contain  more  gluten  than 
the  "  soft "  varieties.  The  gluten  of  wheat  is  said  to  possess  a 
higher  dietetic  value  than  the  gluten  of  corn  or  rye.  Crude  gluten 
may  be  prepared  by  making  a  dough  with  30  Gm.  of  flour  and 
about  15  c.c.  of  water.  This  is  allowed  to  stand  for  an  hour 
and  the  starch  washed  out  by  kneading  it  between  the  fingers  under 
a  gentle  stream  of  tap  water.  The  resultant  product  is  of  a 
grayish  color,  sticky,  tough,  and  elastic,  and  when  pure  is  capable 
of  being  drawn  out  into  long  bands  or  shreds.  The  strength  of  a 
flour, — i.e.,  its  capacity  for  making  a  porous  and  spongy  loaf, — de- 
pends mainly  on  the  quality  and  quantity  of  gluten  it  contains. 
In  the  preparation  of  ordinary  flour  much  of  the  layer  containing 
gluten  is  separated  with  the  coats  of  the  grain  in  the  course  of 
bolting.  Graham  flour,  on  the  other  hand,  being  unbolted,  has 
practically  the  same  constituents  as  the  wheat  grain  itself.  The 
name  "  gluten  flour  "  is  applied  to  one  in  which  the  greater  part 
of  the  starch  is  removed.  Gluten  flours  are  used  by  diabetic 
patients  and  have  a  high  nutritive  value  when  scientifically  pre- 
pared. 

TOXALBUMINS  OR  Toxic  PROTEINS. — Proteins  which  are  ex- 
ceedingly toxic  have  been  isolated,  from  several  plants.  That 
the  protein  substances  possess  poisonous  properties  has  sometimes 
teen  questioned,  but  there  seems  to  be  no  doubt  but  that  true 
toxalbumins  occur  not  only  in  seeds,  but  in  other  parts  of  the 
plant.  The  following  of  these  principles  have  been  rather  care- 
fully studied:  Ricin,  found  in  the  seeds  of  Ricinus  communis; 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       197 


FIG.  112.  Phyto-globulins  (crystaloids)  from  several  sources:  A,  a,  b,  from  the  white 
potato;  B,  a  to  f,  from  the  seeds  of  castor  oil  plant  (Ricinus  communis);  in  b  and  b  are  shown 
different  views  of  the  same  crystal;  C,  a  to  f,  from  the  seeds  of  the  Brazil  nut  (Bertholletia 
excelsd). — After  Dippel  in  "Das  Mikroskop." 


198  A  TEXT-BOOK  OF  BOTANY. 

Abrin,  occurring  in  the  seeds  of  Abrus  precatorius;  Curcin,  in  the 
seeds  of  Jatropha  Curcas;  Crotin,  in  the  seeds  of  Croton  Eluteria; 
and  Robin,  in  the  bark  of  Robinia  Pseud-acacia.  The  pollen 
of  rye  is  also  said  to  contain  a  toxalbumin,  which,  when  adminis- 
tered in  extremely  small  doses,  accentuates  the  symptoms  of  hay 
fever  in  patients  afflicted  with  this  disease.  Under  the  name  of 
"  Vegetable  Agglutinins  "  have  been  brought  those  protein  sub- 
stances which  when  added  to  a  suspension  of  blood-corpuscles  rap- 
idly cause  them  to  agglutinate.  Those  substances  that  possess 
the  same  properties  but  are  not  poisonous  are  known  as 
*; 'Phasins."  (Consult  "The  Vegetable  Proteins,"  by  Osborne; 
and."  Beitrage  zur  Kenntnis  der  vegetabilischen  Hamagglutinine," 
by  R.  Robert.) 

ORIGIN  AND  FORMATION  OF  PLANT  PROTEINS. — It  has  been 
shown  that  carbohydrates  originate  in  chloroplastids  and  are 
formed  under  the  influence  of  sunlight  from  two  simple  substances, 
viz.,  carbon  dioxide  and  water.  Protein  substances,  on  the  other 
hand,  are  not  formed  in  any  definite  organ,  but  arise  in  the  proto- 
plasmic contents  of  the  cell.  This  function  is  not  limited  to  the 
protoplasm  of  green  plants,  as  fungi  also  possess  this  property. 
Furthermore,  proteins  may  be  formed  in  organs  growing  in  the 
dark  as  well  as  those  exposed  to  the  light.  Proteins  arise  through 
the  interaction  of  nitrates,  sulphates,  and  compounds  of  ammonia 
with  either  formaldehyde  or  some  simple  carbohydrate.  It  is 
supposed  that  the  nitrates  and  sulphates  are  decomposed  by  plant 
acids,  furnishing  the  necessary  nitrogen  and  sulphur.  Treub, 
by  reason  of  his  studies  on  Pangium  edule,  has  advanced  the  theory 
that  in  the  construction  of  protein  compounds  the  nitrogen  is 
supplied  by  hydrocyanic  acid.  Apart  from  the  facts  just  men- 
tioned, all  theories  with  regard  to  the  formation  of  proteins  are 
mere  speculations. 

We  are  indebted  to  Emil  Fischer  and  his  students  ("Unter- 
suchungen  iiber  Aminosauren  Polypeptide  und  Proteine,"  Berlin, 
1906)  for  much  information  concerning  the  structure  of  proteins. 
They  have  prepared  synthetically  several  protein-like  substances, 
although  no  natural  occurring  protein  has  as  yet  been  obtained. 
From  these  studies  it  has  been  shown  that  proteins  belong  to  a 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       199 

class  of  chemical  substances  designated  as  "  polypeptides  "  which 
are  formed  by  the  condensation  of  several  amino  acids. 

THE  PERCENTAGE  OF  PROTEIN  IN  PLANTS. — The  amount  of 
protein  in  plants  varies  considerably.  It  is  found  in  greatest 
amounts  in  seedsx  especially  in  the  seeds  of  the  Leguminosse  and 
the  grains  of  cereals.  It  is  also  found  in  surprisingly  large  quanti- 
ties in  a  number  of  the  vegetables.  Were  it  not  for  the  fact  that  the 
fungi  contain  large  quantities  of  water,  they  would  be  considered 
the  most  nutritious  of  all  vegetable  foods,  as  they  contain  in  dry 
substances  over  50  per  cent,  of  protein.  As  the  fresh  mushrooms, 
however,  contain  nearly  90  per  cent,  of  water,  this  brings  the  pro- 
tein content  to  but  about  5  per  cent.  The  percentage  of  protein 
in  dried  material  from  a  number  of  sources  may  be  of  interest,  as 
follows: 

Grains  or  Cereals. — Barley,  7.64  to  17.90;  buckwheat,  9.75  to 
17.25;  corn,  6.41  to  17.02;  oats,  8.35  to  21.88;  rye,  8.39  to  17.38; 
rice,  6.49  to  12.81 ;  and  wheat,  8.30  to  27.88. 

Leguminous  Seeds. — Kidney  beans,  22.53  to  36.46;  lentils, 
14.58  to  34.34;  Hnia  beans,  15.94  to  25.63;  Lupinus  luteus,  15.62 
to  61.27;  peanut,  25.39  to  33.73;  peas,  21.59  to  32-94 ;  soja  beans, 
24.38  to  49.10;  string  beans,  13.06  to  20.19;  and  Vicia  faba,  21.00 
to  36.10. 

Miscellaneous  Seeds. — Beechnut,  about  25 ;  cacao,  7.32  to 
15.94;  cocoanut,  7.75  to  10.90;  chestnut,  5.15  to  15.75;  hazel-nut, 
16.23  to  21.22;  flaxseed,  18.49  to  33.80;  mustard,  15.50  to  39.66; 
coffee,  17.11  to  25.09;  rape-seed,  15.18  to  28.13;  ricinus,  16.35  to 
22.28;  sunflower-seed,  5.67  to  33.89  ;  sweet  almond,  17.50  to  26.62. 

Common  Vegetables. — Asparagus,  15.12  to  33.52;  sugar  beets, 
3.11  to  23.02;  garden  beets,  4.19  to  29.27;  carrots,  3.79  to  16.64; 
cauliflower,  17.23  to  37.75  ;  celery,  8.44  to  25.19 ;  cucumber,  21.38  to 
26.06;  garlic,  1.17  to  13.50;  parsnips,  6.38  to  13.50;  potatoes,  2.21 
to  17.59;  sweet  potatoes,  1.70  to  19.61;  radish,  13.00  to  22.13; 
spinach,  27.50  to  45.33;  and  turnips,  4.01  to  21.00. 

Fruits. — Apples,  0.22  to  1.32;  apricots,  0.13  to  1.79;  bananas, 
3.37  to  7.75;  cherries,  0.97  to  4.75;  cucumber,  21.38  to  26.06; 
currants,  o.n  to  1.44;  figs,  0.90  to  2.58;  gooseberries,  .21  to  .94; 
grapes,  0.22  to  1.20;  lemons,  0.49  to  2.90;  musk  melon,  4.69  to 
22.23;  oranges,  4.83  to  2.24;  peaches,  0.23  to  1.67;  pears,  0.19  to 


200  A  TEXT-BOOK  OF  BOTANY. 

0.56;  plums,  0.27  to  0.99;  prunes,  0.59  to  0.69;  pumpkin,  30.31  to 
36.25;  raspberries,  0.18  to  1.47;  strawberries,  0.35  to  1.05. 

Spices. — Anise,  16.31  to  18.15;  capsicum,  11.20  to  16.81 ; 
cardamom,  5.50  to  14.77;  caraway,  19.43  to  20.25;  cloves,  4.73  to 
7.06;  cinnamon,  i.oi  to  8.00;  coriander,  10.94  to  12.03;  curcuma, 
9.18  to  12.56;  dill,  6.75  to  21.56;  fennel,  16.28  to  17.19;  ginger, 
3.27  to  10.83 ;  mace,  4.55  to  7.80;  mustard,  15.50  to  39.66;  nutmeg, 
5.16  to  7.12;  pepper,  15.18;  paprika,  10.9  to  27.16. 

Miscellaneous. — Agaricus  campestris,  20.63  to  62.94;  sea- 
weeds, 5.56  to  39.25. 

CALCIUM  CARBONATE  occurs  occasionally  in  the  form  of  a  cell- 
content,  being  present  in  tracheae  or  vessels  and  tracheids  of  the 
heart  wood,  as  well  as  in  the  medullary  rays  and  pith  cells  of 
certain  plants.  In  this  form  it  is  rather  characteristic  of  one  or 
more  genera  in  the  following  families :  Aceraceae,  Anonaceae, 
Cornaceae,  Cupuliferae,  Rosaceae,  Salicaceae,  Sapotaceae,  Urti- 
caceae, and  Zygophyllaceae.  When  present  it  almost  completely 
fills  the  cells,  and  may  be  overlooked  or  referred  to  as  resin  unless 
its  identity  is  proved  by  the  use  of  certain  reagents.  Like  the 
other  carbonates,  it  dissolves  with  effervescence  on  the  addition 
of  hydrochloric  acid,  nitric  acid,  acetic  acid,  etc.,  and  in  this  way 
may  be  detected. 

Calcium  carbonate  is  present  in  special  structures  known  as 
Cystoliths.  The  latter  are  protuberances  of  the  cell  wall  into  the 
cell,  and  consist  of  a  stalk  and  a  body  (Fig.  113).  The  stalk 
consists  of  a  simple  core  of  cellulose  on  which  more  or  less  silica 
is  deposited.  The  upper  or  body  portion  consists  of  a  more  or 
less  irregular  spherical  or  ellipsoidal  deposit  of  calcium  carbonate. 
These  are  found  in  the  parenchyma  cells  in  roots  and  barks  and  the 
subepidermal  cells  of  leaves.  They  are  also  found  in  epidermal 
cells,  as  in  the  short  hairs  of  Cannabis  sativa.  Cystoliths  occur 
in  certain  genera  of  the  Acanthaceae,  Borraginaceae,  Cucurbi- 
taceae,  Gesneraceae,  Oleaceae,  Ulmaceae,  Moraceae,  and  Urticaceae. 

Cystoliths  occur  in  a  number  of  modifications,  and,  while  they 
are  usually  simple,  yet  in  some  of  the  Acanthaceae  and  Urticaceae 
branched  cystoliths  occur.  In  some  of  the  genera  of  the  Cucur- 
bitaceae  2-  to  4-adjoning  cells  may  have  cystoliths,  and  hence  are 
known  as  "  double  cystoliths."  The  cystoliths  found  in  hairs,  as 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       201 

in  Cannabis  sativa,  do  not  usually  have  a  stalk,  and  are  known 
as  "  hair  cystoliths."  The  latter  are,  furthermore,  variously  modi- 
fied, and  may  have  incrustations  of  either  calcium  carbonate  or 
silica  or  a  mixture  of  both  of  these  substances.  In  the  Begoniaceae 
occurs  a  certain  form  of  structure  resembling  a  cystolith,  but  it  is 
uncalcified,  and  consists  of  a  mucilaginous  substance  which  is 


r, 


f 


FIG.  113.  Cystolith.  A  cross  section  of  a  portion  of  the  leaf  of  Ficus  elastica  showing 
cells  of  the  upper  epidermis  (e),  cells  of  the  hypodermal  layer  (h),  among  which  is  a  large 
cell  containing  a  cystolith  (c);  palisade  cells  (ch). — After  Sachs. 


sometimes  more  or  less  impregnated  with  resin.  These  are  known 
as  "  cystotyles."  The  protuberances  found  on  the  walls  of 
certain  epidermal  cells  and  in  the  subsidiary  cells  of  hairs  may 
be  either  calcified  or  silicified,  and  occur  in  the  families  containing 
true  cystoliths  and  also  some  genera  of  the  following:  Com- 
positae,  Campanulaceae,  Oleaceae,  Leguminosae,  Hydrophyllaceae, 


202  A  TEXT-BOOK  OF  BOTANY. 

Scrophulariaceae,  Polemoniaceae,  Verbenaceae,  Euphorbiaceae,  and 
Urticaceae. 

SILICA  is  seldom  found  as  a  cell-content,  and  when  present 
never  occurs  as  a  crystalline  deposit,  being  usually  in  the  form  of 
amorphous  masses,  termed  "silica-bodies"  (Fig.  109).  The 
latter  arise  either  in  the  cell-sap  or  the  silica  is  deposited  on  the 
cell-wall,  ultimately  filling  the  lumen  of  the  cell.  In  the  palms  the 
silica-bodies  resemble  stalkless  cystoliths  (Fig.  109,  C).  They  may 
also  occur  in  the  form  of  long  rods,  being  more  or  less  fusi- 
form or  rectangular,  or  in  the  form  of  discs  showing  a  more  or  less 
sphero-crystalline  structure,  or  in  other  special  forms  (Fig.  109). 
Silica-bodies  have  been  found  in  the  Palmae,  Orchidaceae,  Podoste- 
maceae,  and  Rutacese.  Silica  is  insoluble  in  any  of  the  ordinary 
solvents,  being  dissolved  only  by  hydrofluoric  acid.  On  incinerating 
the  tissues  it  is  not  destroyed.  The  presence  of  silica  may  be  deter- 
mined readily  upon  heating  sections  with  sulphuric  acid  or  any 
reagent  that  destroys  organic  matter. 

Silica  usually  occurs  as  an  incrustation  in  the  cell-wall,  being 
found  in  epidermal  cells,  spinose  hairs,  and  even  the  palisade  and 
mesophyll  cells  of  quite  a  number  of  plants.  Siliceous  walls  are 
rather  characteristic  of  the  genera  of  the  following  families : 
Acanthaceae,  Aristolochiaceae,  Bignoniaceae,  Borraginaceae, 
Burseraceae,  Calycanthaceae,  Campanulaceae,  Chloranthaceae, 
Combretaceae,  Compositae,  Cucurbitaceae,  Dilleniaceae,  Euphor- 
biaceae,  Gesneraceae,  Goodeniaceae,  Hydrophyllaceae,  Leguminosae, 
Loranthaceae,  Magnoliaceae,  Melastomaceae,  Menispermaceae, 
Oleaceae,  Piperaceae,  Proteaceae,  Rosaceae,  Rubiaceae,  Santalaceae, 
Saxifragaceae,  Urticaceae,  and  Verbenaceae. 

TANNINS  AND  TANNIDES. — There  is  a  group  of  water-soluble 
principles  that  occur  in  the  cell-sap,  especially  of  parenchyma 
cells,  of  a  large  number  of  plants.  They  are  derivatives  of  phenol 
and  phenol  acids,  and  give  either  dark  blue  or  green  precipitates 
with  solutions  of  ferric  chloride.  They  were  formerly  designated 
as  tannins  and  distinguished  according  to  the  plants  from  which 
they  were  obtained ;  thus  we  had  chestnut  tannin,  oak  tannin,  etc. 
Recent  studies  on  the  constitution  of  these  substances  show  that 
there  are  two  principal  groups  of  tannins,  ( I )  being  in  the  nature 
of  glucosides  and  (2)  the  other  not  yielding  any  dextrose  on 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       203 

hydrolysis  with  acids.  Both  of  these  groups  may  be  subdivided 
into  two  classes,  namely,  (A)  those  which  probably  are  deriva- 
tives of  protocatechuic  acid  and  (B)  those  which  are  derivatives 
of  gallic  acid.  A  class  name  has  been  given  to  include  these 
subgroups,  namely,  "  tannides  "  or  "  tannoids."  The  .first  sub- 
group (A)  would  then  include  the  protocatechuic-tannides  or 
-tannoids,  and  the  second  (B)  would  comprise  the  gallic- tannides 
or  -tannoids.  In  working  out  a  system  of  classification  of  this 
kind  Kunz-Krause  (Swheiz.  Woch.  f.  Chem.  u.  Pharm.,  1898,  p. 
424)  has  arranged  all  of  the  possible  tannides  or  tannoids  and 
has  given  the  formulae  for  a  number  which  have  not  yet  been 
found  in  nature. 

CHEMICAL  PROPERTIES  OF  TANNINS. — The  tannins  are  amor- 
phous substances  and  do  not  form  crystalline  salts.  They  are 
soluble  in  water,  alcohol,  ethyl  acetate,  or  a  mixture  of  alcohol 
and  ether.  They  are  almost  insoluble  in  anhydrous  ether,  chloro- 
form, and  the  other  immiscible  solvents.  The  solutions  give  dis- 
tinct color  reactions  or  precipitates  with  ferric  chloride,  stannous 
chloride,  and  acetates  of  copper  and  lead.  They  form  soluble 
compounds  with  iodine  and  prevent  the  latter  from  giving  the 
characteristic  blue  reaction  with  starch.  Solutions  of  tannin 
give  insoluble  precipitates  with  cinchonine  and  other  organic 
bases.  Tannins  are,  furthermore,  especially  in  alkaline  solutions, 
powerful  reducing  agents,  their  resulting  products  being  of  a 
dark  red  or  yellowish-red  color. 

Upon  treatment  of  tannins  with  dilute  acids,  or  fusing  with 
the  alkali  hydroxides,  or  heating  alone,  several  classes  of  products 
are  formed. 

I.  When  heated  in  a  sealed  tube  at  100°  C.  solutions  of  tannin 
in  a  I  per  cent,  solution  of  hydrochloric  acid  yield  either  crystal- 
lizable  acids,  or  phlobaphenes,  or  insoluble  red  substances.  (A) 
The  following  glucosidal  tannins  yield  crystallizable  acids :  The 
tannin  from  nut-galls,  divi-divi  (fruit  of  Casalpinia  coriaria), 
myrobalans  (fruit  of  Terminalia  Chebula),  rind  of  pomegranate 
fruit,  and  coffee.  (B)  Phlobaphene  is  a  reddish,  or  brownish-red, 
amorphous  substance  formed  from  the  tannin  of  willow  bark.  It 
is  insoluble  in  water  but  soluble  in  alcohol,  dilute  solutions  of 
the  alkalies  and  alkali  carbonates,  and  solutions  of  borax.  (C) 


204  A  TEXT-BOOK  OF  BOTANY. 

Quite  a  number  of  tannins  yield  a  reddish,  amorphous  substance 
which  precipitates  out  of  the  acid  solution  and  is  insoluble  in 
water,  alcohol,  and  solutions  of  the  alkalies.  Derivatives  of  this 
kind  are  obtained  from  the  tannin  of  kino,  krameria,  etc. 

2.  When  tannins  are  fused  with  potassium  or  sodium  hydrox- 
ide several  classes  of  products  are  formed,  depending  on  the  con- 
stitution of  the  tannin.     (A)  Protocatechuic  acid  is  formed  not 
only  on  the  fusion  of  certain  tannins,  but  may  be  prepared  from 
other    plant    substances,    as    vanillin,    asafoetida,     myrrh,    etc. 
Usually  other  substances  are   formed   in  the   interaction,  these 
being  either  acetic  acid  or  phloroglucinol.     In  this  class  are  in- 
cluded the  most  of  the  tannins,  which  on  heating  with  dilute 
acids  yield  either  phlobaphenes  or  insoluble  red  substances.     (B) 
Pyrogallol,  which  is  commercially  prepared  by  the  dry  distillation 
of  gallic  acid,  is  also  formed  from  the  glucosidal  tannins  which 
yield  crystallizable  acids  in  acid  solutions. 

3.  Upon  carefully  heating  tannins  .to  a  temperature  of  190° 
to  200°  C.  they  are  decomposed  and  yield  two  distinct  classes  of 
derivatives,  being  either  (A)  pyrocatechol   (a  diatomic  phenol) 
or  (B)  pyrogallol  (a  triatomic  phenol).    Both  of  these  substances 
are   crystalline   and   may   be   sublimed   unchanged.      They   are, 
furthermore,  both  soluble  in  water,  alcohol,  and  ether,  and  are 
distinguished  by  giving  very  characteristic  reactions  with  certain 
reagents.     Solutions  of  pyrocatechol  are  colored  dark  green  with 
ferric-alum  and  greenish   with   copper  sulphate   +   ammonium 
hydrate,  or  concentrated  sulphuric  acid.     Pyrogallol  is  colored 
bluish-black  with  ferric-alum,  becoming  green  and  finally  brown ; 
brownish  with  copper  sulphate  +  ammonium  hydrate,  or  sul- 
phuric acid,  and  becoming  violet  with  lime  water,  rapidly  chang- 
ing to  brown.    Pyrocatechol  is  formed  from  those  tannins  which 
produce  protocatechuic  acids  on  fusion  with  potassium  hydroxide 
and  phlobaphenes  or  insoluble  red  substances  on  treatment  with 
acids.     Pyrogallol  is  formed  on  heating  those  tannins  which  also 
yield  pyrogallol  on  fusion  with  potassium  hydroxide  and  yield 
either  gallic  acid  or  ellagic  acid  on  hydrolysis  with  acids. 

MICROCHEMISTRY  OF  TANNINS. — Tannin  ocurs  as  a  constituent 
of  the  cell-sap,  and  the  cells  containing  it  may  be  determined  by 
use  of  dilute  solutions  of  methylene  blue,  as  proposed  by  Pfeffer, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      205 

which  colors  the  cell-sap  blue,  afterward  precipitating  the  tannin. 
This  reagent  has  the  advantage  that  when  used  in  very  dilute 
solution  ( i  part  methylene  blue  to  500,000  of  water)  it  does  not 
injure  the  protoplasm  of  the  living  cells,  so  that  the  cut  end  of  a 
twig  may  be  placed  in  the  solution  for  I  to  24  hours  and  sections 
examined  from  time  to  time.  Another  reagent  that  is  very 
satisfactory  in  the  examination  of  living  material  is  a  solution  of 
ammonium  carbonate,  which  causes  a  precipitation  of  the  tannin 
in  the  cells  in  the  form  of  very  small  globules  or  rods.  This  solu- 
tion may  be  used  either  directly  upon  sections  or  by  placing  freshly 
cut  stems  in  dilute  solutions  ( I  part  ammonium  carbonate  and 
200  parts  water).  Ammonium  carbonate  does  not  precipitate 
gallic  acid  and  therefore  may  be  advantageously  used  in  the  study 
of  the  development  of  tannin  and  related  substances,  as  in  galls. 
The  following  reagents  also  give  distinct  reactions  for  tannin. 
Copper  acetate  in  concentrated  aqueous  solutions  is  one  of  the 
very  best  reagents  for  the  localization  of  tannin  cells.  It  is  em- 
ployed by  allowing  the  leaves  or  twigs  to  remain  in  the  solution 
for  some  days,  when  the  tannin  forms  a  reddish-brown  precipitate 
in  the  cells.  Ferric  chloride  and  ferric  acetate  also  precipitate 
tannin.  Moeller  has  suggested  the  use  of  a  solution  of  iron 
chloride  in  anhydrous  ether,  the  cut  pieces  of  the  stems  and  leaves 
being  placed  directly  in  this  reagent.  Potassium  bichromate  and 
chromic  acid  in  dilute  solutions  give  yellowish-brown  or  blackish- 
brown  precipitate  with  tannin. 

DISTRIBUTION  OF  TANNIN. — There  are  very  few  plants  in 
which  tannin  does  not  occur  in  some  of  the  parts  or  at  least  in  cer- 
tain cells  during  some  period  in  their  development.  This  is  fre- 
quently noted  in  making  sections  of  plant  material  with  a  razor ;  the 
liberated  cell-sap  is  colored  a  dark  blue.  It  is  found  in  the  form  of 
highly  refracting  globules  in  the  Zygnemaceae  and  other  Algae.  It 
occurs  in  relatively  large  amounts  in  some  of  the  ferns,  and,  with 
the  exception  of  the  Monocotyledons,  is  widely  distributed  in  the 
Spermophytes.  As  tannin  is  widely  used  in  the  making  of  leather 
and  as  a  mordant  .in  dyeing,  etc.,  it  is  extracted  from  various 
plants  and  is  an  article  of  commerce.  The  following  are  some 
of  the  important  tannin-yielding  plants:  The  bark  of  hemlock 
(Tsuga  canadensis,  Fam.  Pinaceae)  yields  nearly  14  per  cent,  of 


206  A  TEXT-BOOK  OF  BOTANY. 

tannin;  the  bark  of  several  species  of  Pinus  (Fam.  Pinacese) 
growing  in  southern  Europe  yields  7  to  10  per  cent,  of  tannin; 
the  barks  of  the  white  spruce  (Picea  canadensis)  of  Canada,  of 
the  larch  (Larix  laricina)  of  northern  and  northwestern  part  of 
United  States  and  Canada,  and  of  the  fir  (Abies  balsamea)  yield 
similar  amounts  of  tannin  as  the  barks  of  hemlock  and  pine.  The 
wood  of  chestnut  (Castanea  dentata,  Fam.  Fagaceae)  yields  8'  to 
10  per  cent,  of  tannin ;  the  bark  of  several  species  of  Salix  (Fam. 
Salicacese)  growing  in  northern  Europe  yields  3  to  12  per  cent, 
of  tannin ;  the  bark  of  chestnut  oak,  white  oak,  red  oak,  etc. 
(Fagacese),  yields  12  to  15  per  cent,  of  tannin;  the  scaly  in- 
volucres or  acorn-cups  (under  the  name  of  "  Valonia ")  of 
several  species  of  Quercus  growing  in  southern  Europe  and 
Levant  yield  25  to  35  per  cent,  of  tannin ;  the  fruit  of  Terminalia 
Chebula  (under  the  name  of  "  Myrobalans ")  yields  35  to  40 
per  cent,  of  tannin  ;  the  stems  and  leaves  of  several  species  of  Rhus 
(Anacardiacese)  yield  16  to  24  per  cent,  of  tannin;  the  fruit  of 
Ccesalpinia  coriaria  (Fam.  Leguminosse)  (under  the  name  of 
"divi-divi")  yields  30  to  50  per  cent,  of  tannin;  the  wood  and 
the  bark  of  several  species  of  Schinopsis  (Fam.  Apocynaceae) 
growing  in  South  America  yield  from  15  to  23  per  cent,  of  tannin, 
which  is  usually  found  in  commerce  in  the  form  of  an  extract 
known  as  "  Quebracho  Extract  " ;  the  bark  of  the  common  horse- 
chestnut  (Aisculus  Hippocastanum,  Fam.  Sapindaceae)  yields 
considerable  tannin,  and  is  employed  in  Italy ;  the  bark  of  Myrica 
Nagi  (Fam.  Myricaceae)  contains  n  to  14  per  cent,  of  tannin; 
the  bark  of  Malpighia  glabra  (Malpighiaceae)  (under  the  name 
of  "Nance  bark")  is  used  in  Mexico  and  yields  about  26  per 
cent,  of  tannin;  the  bark  of  Stryphnodendron  polyphyllum  (Fam. 
Leguminosae)  yields  about  30  per  cent,  tannin.  The  tannin  of  a 
number  of  other  plants  has  been  investigated,  some  of  these  being 
used  in  medicine,  as  granatum,  catechu,  kino,  krameria,  tor- 
mentilla,  gambir,  etc.  (see  Vol.  II). 

GALLS. — There  are  a  number  of  excrescences,  found  upon  the 
leaves  and  twigs  of  a  number  of  plants,  termed  galls.  These  result 
from  injuries  caused  chiefly  by  insects,  and  are  therefore  in  the 
nature  of  pathological  products.  Galls  which  are  formed  on 
trees  which  in  themselves  contain  considerable  tannin  usually 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       207 

yield  very  large  amounts  of  tannin.  Nut-galls  formed  on  certain 
species  of  oak  yield  65  per  cent,  of  tannin.  The  Japanese  galls 
and  Chinese  galls  formed  on  the  leaf  stalks  and  young  branches 
of  some  species  of  Rhus  contain  about  70  per  cent,  of  tannin. 
The  galls  found  occasionally  on  sumach  (Rhus  glabra),  a  shrub 
abundant  in  North  America,  yield  over  60  per  cent,  of  tannic 
acid.  The  tannins  obtained  from  excrescences  of  this  character 
were  at  one  time  called  "  pathological  tannins,"  to  distinguish 
them  from  the  tannins  formed  naturally  in  the  living  plant,  and 
which  were  called  "  physiological  tannins."  In  the  light  of  the 
studies  on  the  several  tannins  this .  terminology  is  no  longer 
accepted. 

INCLUSION  CELLS  AND  TANNIN  IDIOBLASTS. — In  a  number  of 
plants  occur  special  cells  which  vary  considerably  in  form  and  con- 
tents, but  are  distinguished  by  giving  reactions  for  tannin.  In- 
clusion cells  were  first  described  by  Fliickiger  in  the  fruit  of 
Ceratonia  Siliqua.  These  occur  in  the  form  of  long  tubes,  which 
are  easily  separated  from  the  pulp,  and  the  yellowish  contents 
are  colored  blue  with  solutions  of  ferrous  sulphate  or  ferric 
chloride.  Recently  Hanausek  has  contributed  several  papers  on 
the  distribution  of  inclusion  cells  in  a  number  of  different  plants. 
In  the  leaves  of  Pistacia  Lentiscus  he  found  (Ber.  d.  d.  Bot.  Ges., 
1914,  p.  117)  that  the  upper  row  of  palisade  cells  and  the  loose 
mesophyll  cells  (Fig.  114,  A)  contain  numerous  somewhat 
elongated,  transversely  striated  bodies,  which  completely  fill  the 
cells.  These  are  colored  dark  green  or  blackish  with  ferric 
chloride  and  a  pale  violet  with  a  solution  of  potassium  hydrate. 
The  contents  dissolve  on  heating,  changing  to  a  brownish  color. 
They  are  also  partly  soluble  in  concentrated  sulphuric  acid,  and 
with  solutions  of  vanillin  +  hydrochloric  acid  the  contents  are 
colored  red.  They  are  not  completely  soluble  in  hot  solutions  of 
potassium  hydroxide,  there  always  remaining  a  small,  colorless 
portion.  The  inclusions  in  the  date  (Fig.  114,  B)  and  tamarind 
resemble  those  found  in  the  fruit  of  St.  John's  Bread  (Ceratonia) 
and  leaves  of  Pistacia.  Inclusions  have  been  found  in  the  seed 
coat  of  Pimenta  and  one  or  more  fruits  in  the  following  families : 
Anonacese,  Anacardiacese,  Ebenaceae,  Elseagnacese,  Leguminosse, 
Palmse,  Rhamnacese,  and  Rosaceae. 


208 


A  TEXT-BOOK  OF  BOTANY. 


TANNIN  IDIOBLASTS  were  first  observed  by  Zopf  in  a  number 
of  genera  of  the  Fumariaceae  (Fig.  115).  These  are  somewhat 
analogous  to  and  resemble  the  latex  or  pigment  cells  in  the  Papa- 
veracese.  They  develop  in  the  meristematic  cells  of  certain  tissue 
systems  and  remain  constant  throughout  the  life  of  the  plant.  The 


FIG.  114.  Inclusion  Cells:  A,  section  of  leaf  or  Pistacia  Lentiscus  showing  numerous 
inclusion  cells  (in)  in  the  upper  palisade  layer  and  cells  of  mesophyll;  calcium  oxalate 
(kr);  palisade  layers  (pa) ;  loose  mesophyll  (m) ;  fibro vascular  bundle  (i);  upper  epidermis 
(ep);  granules  of  fatty  substance  (i);  lower  epidermis  (ep);  stoma  (sp).  B,  Inclusion  cells 
or  tubes  (k,  1,  m)  in  the  fruit  of  the  date  palm;  k,  showing  a  homogeneous  amorphous 
content;  1  and  m,  separation  of  irregular  inclusion  masses  in  form  of  projections  from  the 
wall. — After  Hanausek. 

cells  vary  in  shape,  composition  of  wall,  and  color  of  contents. 
They  may  be  either  short,  isolated  cells  or  occur  in  chains;  or 
they  may  become  elongated,  resembling  fibers.  The  walls  may  be 
composed  of  cellulose  or  contain  a  certain  amount  of  lignin  or 
suberin.  Some  of  the  cells  may  contain  a  nucleus.  The  cell-sap 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      209 
A  D 


FIG.  115.  Idioblasts  containing  tannin  and  anthocyanin:  A-D,  idioblasts  in  primary 
cortex  of  root  of  Corydalis  ochroleuca,  showing  a  short,  thin-walled  cell  with  reddish  sap 
(A,  t),  and  a  long  fiber  with  yellowish  content  (A,  e);  three  short,  thick- walled  idioblasts 
(B)  with  a  reddish  cell-sap;  a  short  fiber  with  yellowish  contents  (C)  and  transverse  sections, 
through  an  idioblast  (D),  showing  the  thick,  porous  walls.  E,  a  portion  of  an  idioblast, 
with  thick,  porous  walls,  from  the  pith  of  Fumaria  muralis.  F  to  H,  idioblasts  in  Parnassia 
palustris;  F,  portion  of  epidermis  of  leaf  showing  5  idioblasts  (t)  with  colorless  but  highly 
refracting  tannin  content;  G,  portion  of  epidermal  layer  of  corolla  tube  with  reddish  an- 
thocyanin idioblasts  (t);  H,  portion  of  epidermal  layer  at  the  base  of  corolla  tube  with 
very  long  idioblasts  (t)  containing  a  red-colored  cell-sap. — After  W.  Zopf,  "tfber  die 
Gerbstoff-  und  Anthocyan-Behalter  der  Fumariaceen  und  einiger  anderen  Pflanzen," 
in  Bibliotheca  Botanica. 

14 


210  A  TEXT-BOOK  OF  BOTANY. 

may  be  either  colorless  or  of  an  intensely  yellow  or  bright  red 
color,  giving  a  distinct  reaction  for  tannin.  The  cell-sap  is  soluble 
in  water  and  in  alcohol  and  gives  an  acid  reaction.  In  the  yellow 
idioblasts  upon  treatment  with  nitric  acid  it  is  colored  orange-red, 
changing  to  reddish-brown ;  with  concentrated  sulphuric  acid  it 
becomes  orange-red  and  finally  of  a  rose-red  or  crimson 
color;  with  solutions  of  the  alkalies  it  becomes  greenish,  and  it  is 
precipitated  with  solutions  of  potassium  bichromate,  ferric  acetate, 
or  ferrous  sulphate,  the  precipitates  resembling  those  found  with 
tannin.  Zopf  found  that  the  tannin  idioblasts  may  possess  either 
a  colorless  content  or,  in  addition,  have  a  yellow  coloring  prin- 
ciple (yellow  anthocyanin)  or  a  red  pigment  (red  anthocyanin). 
He  considers  that  the  yellow  pigment  is  derived  from  a  colorless 
chromogen  and  that  the  red  pigment  may  be  formed  from  either 
a  colorless  chromogen  or  from  yellow  anthocyanin.  Further- 
more, he  concludes  that  there  is  a  relationship  in  the  Fumariaceae 
between  the  anthocyanin  and  tannin,  as  the  two  constituents  are 
always  found  in  the  same  cell.  It  is  rather  interesting  to  note 
that  chloroplasts  may  be  found  in  the  idioblasts,  and  that  sugar 
is  also  a  constituent  in  the  idioblasts,  occurring  in  the  young  roots 
and  stems  of  Diclytra  spectabilis. 

Tannin  idioblasts  are  found  in  the  palisade  tissues  of  leaves 
or  in  the  parenchyma  cells  of  roots  and  stems  of  some  of  the 
genera  in  the  Geraniaceae,  Celastraceae,  Rhamnaceae,  Legumi- 
nosse,  Solanaceae,  Rubiaceae,  Scrophulariaceae,  Polygonacese, 
Aristolochiaceae,  Piperaceae,  Euphorbiaceae  and  Moraceae. 

THE  FIXED  OILS,  FATS,  AND  WAXES  include  a  group  of  sub- 
stances which  are  widely  distributed  in  plants,  occurring  especially 
abundant  in  seeds,  fruits,  and  barks.  They  are  distinguished  by 
the  fact  that  in  their  chemical  constitution  they  possess  radicals 
of  the  fatty  acids.  In  the  diatoms,  Vaucheria,  and  some  of  the 
other  lower  plants  fixed  oils  arise  in  the  chromatophores  in  place 
of  starch,  thus  being  the  first  visible  product  of  photosynthesis. 
Fixed  oils  usually  occur  in  reserve  cells  as  in  seeds  and  the 
parenchyma  and  medullary  ray  cells  of  roots  and  rhizomes.  They 
are  either  found  in  the  vacuoles  of  the  protoplasm  or  are  formed 
in  the  cell-wall,  and  usually  are  liberated  in  the  form  of  globules 
upon  healing  the  sections  or  treating  them  with  solutions  of 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       211 

hydrated  chloral  or  sulphuric  acid.  The  fixed  oils  remain 
liquid  at  ordinary  temperatures,  whereas  the  fats  tend  to  solidify, 
and  are  occasionally  found  in  the  form  of  crystals  in  plant  cells 
(Fig.  116).  '  Both  of  these  classes  are  fatty  acid-esters  of 
glycerin,  whereas  the  waxes  are  combinations  of  fatty  acids  and 


FIG.  116.  Crystals  of  fixed  oils:  A,  section  of  seed  of  the  oil  palm  (Elceis  guineensis) 
treated  with  an  alcoholic  solution  of  iodine  and  very  dilute  sulphuric  acid,  showing  stone 
cells  (sc) ;  cells  with  homogeneous  brown  content  (sa) ;  cells  with  yellowish  granular  content 
(sa');  and  cells  of  endosperm  (en)  hav;.ng  porous  walls  (x),  and  containing  phytoglobulins 
(crystalloids)  (P,  p),  associated  with  needle  aggregates  of  the  fatty  acids.  B,  cross  section 
of  a  cotyledon  of  cacao,  heated  in  a  solution  of  potassium  hydroxide,  showing  the  epidermal 
layer  (ep)  with  hair  (d),  phytoglobulin  (crystalloids)  (al)  and  aggregates  of  fatty  acids  (f). 
C,  a  few  cells  of  the  cotyledons  of  ripe  cacao  seeds  mounted  in  glycerin,  showing  separation 
of  sphere-crystals  of  fatty  acids  in  the  oil  and  starch-bearing  cells  of  endosperm. — After 
Hanausek. 

some  alcohol  other  than  glycerol  (glycerin).  According  to  this 
distinction  some  waxes  as  myrtle  wax,  obtained  from  the  berries 
of  Myrica  cerifera,  are  classed  among  the  fats,  it  being  a  mixed 
glyceride  of  palmitic  and  lauric  acids. 

The  fatty  acids  which  enter  into  the  constitution  of  the  fixed 
oils  and  fats  belong  to  more  than  one  series  of  hydrocarbons. 


212  A  TEXT-BOOK  OF  BOTANY. 

The  following  acids  are  present  in  the  vegetable  oils  and  fat. 
Normal  caproic  acid  (C6H12O2),  Caprylic  acid  (C8H16O2),  and 
Capric  acid  (C10H20O2)  are  found  in  cocoa-nut  oil,  expressed 
from  the  seeds  of  the  cocoa-nut  (Cocos  nucifera),  and  in  palm- 
nut  oil,  obtained  from  the  oily  sarcocarp  of  the  drupes  of  the 
palm,  Elais  guineensis. 

LAURIC  ACID  (C12H24O2)  occurs  in  laurel-nut,  obtained  from 
the  seeds  of  Calophyllum  Inophyllum  (Fam.  Guttiferse),  a  plant 
growing  in  the  East  Indies  and  Cochin  China.  It  is  also  found  in 
cocoa-nut  oil  and  certain  other  vegetable  oils. 

MYRISTIC  ACID  (C14H28O2)  is  found  in  certain  vegetable  fats, 
especially  in  nutmeg  and  mace.  This  oil  forms  crystalline  salts 
with  both  potassium  and  barium. 

PALMITIC  ACID  (C16H32O2)  occurs  combined  with  glycerol  in 
a  large  number  of  vegetable  oils,  especially  in  palm-nut  oil,  and 
Japan  wax.  The  latter  is  obtained  from  fruits  of  Rhus  vernicifera 
and  R.  chinensis.  It  is  also  found  in  myrtle  wax,  which  occurs 
as  an  incrustation  on  the  fruits  of  the  wax  myrtle  (Myrica 
cerifera)  and  bayberry  (M.  carolinensis) .  This  acid  is  not  very 
readily  soluble  in  petroleum  ether.  A  crystalline  silver  salt  is 
obtained  by  adding  an  alcoholic  solution  of  silver  nitrate  to  an 
alcoholic  solution  of  ammonium  palmitate. 

STEARIC  ACID  (C18H36O2)  occurs  as  a  glyceride  in  cacao  butter 
obtained  from  chocolate  seeds,  and  in  "  Shea  butter  "  obtained 
from  the  seeds  of  Butyrospennum  Parkii,  a  tree  growing  in  Upper 
Guinea  and  in  the  region  of  the  Nile. 

ARACHIDIC  ACID  (C20H40O2)  occurs  combined  with  glycerol  in 
peanut  oil  and  other  vegetable  fats.  The  acid  is  soluble  in  boiling 
alcohol,  ether  chloroform,  benzene,  and  petroleum  ether.  It 
forms  crystalline  salts  of  copper  and  silver. 

BEHENIC  ACID  (C22H44O2)  occurs  as  a  glyceride  in  "oil  of 
Ben  "  expressed  from  the  seeds  of  Moringa  pterygosperma,  a 
plant  of  the  East  and  West  Indies.  This  oil  is  used  for  the 
preparation  of  cosmetics,  by  perfumers  for  extracting  odorous 
substances,  and  as  a  lubricating  oil  for  clocks. 

LIGNOCERIC  ACID  (C24H48O2)  occurs  as  a  glyceride  in  peanut 
oil,  and  is  distinguished  from  arachidic  acid  in  being  slightly 
soluble  in  cold  alcohol. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       213 

TIGLIC  ACID  (C5H8O4)  occurs  as  a  glyceride  in  croton  oil, 
and  is  soluble  in  water. 

HYPCXLEIC  ACID  (C16H30O2)  occurs  combined  with  glycerol  in 
peanut  oil  and  in  corn  oil.  It  is  soluble  in  cold  alcohol  and 
crystallizes  in  needles. 

LYCOPODIC  ACID  occurs,  as  a  glyceride,  in  lycopodium  spores, 
and  is  related  to  hypogseic  acid. 

OLEIC  ACID  (C18H34O2)  occurs  as  a  glyceride  in  many  vege- 
table oils.  The  glyceride  of  oleic  acid  occurs,  as  a  rule,  in  larger 
quantities  in  most  fixed  oils  than  any  other  glyceride,  being  present 
in  olive  oil  to  the  extent  of  90  per  cent.  It  is  also  found  in  a  large 
number  of  seeds,  principally  in  cotton  seed,  hazel-nut,  peanut, 
sesame,  walnut,  corn,  tea  seed,  almond,  and  the  kernels  of 
apricot,  peach,  and  plum.  These  oils  are  generally  grouped  to- 
gether and  known  as  the  "  olive  oil  group."  The  sodium  and 
barium  salts  of  oleic  acid  are  crystalline. 

RAPIC  ACID  (C18H34O2)  and  ERUCIC  ACID  (C22H42O2)  occur 
combined  with  glycerol  in  the  oil  obtained  from  rape  or  colza 
seed  and  in  other  Cruciferous  seeds. 

LINOLEIC  ACID  (C18H32O2)  is  the  principal  acid  of  the  gly- 
cerides  forming  the  "  linseed  oil  group  "  or  "  drying  oils."  The 
acid  which  is  best  known  is  that  obtained  from  flaxseed  or 
linseed,  the  oil  of  which  contains  from  80  to  85  per  cent,  of 
linoleic  acid  or  its  isomers.  Linoleic  acid  is  also  present  in  the 
fixed  oil  occurring  in  the  seeds  of  the  following  plants :  Hemp, 
walnut,  pine  (Pinus  sylvestris),  fir  (Abies  balsamea),  poppy, 
sarBower,  sunflower,  and  seeds  of  a  number  of  species  of 
Aleurites.  The  seeds  of  Aleurites  moluccana  yield  the  "  candle 
nut  oil "  of  the  South  Sea  Islands,  and  the  seeds  of  A.  cor  data 
yield  the  "  tung  oil  "  (Chinese  wood  oil  or  Japanese  wood  oil)  of 
China  and  Japan. 

RICINOLEIC  ACID  (C18H34O3)  occurs  as  a  glyceride  in  castor 
oil,  and  is  the  principal  constituent  of  this  oil.  It  is  also  present 
in  the  seeds  of  other  Euphorbiaceous  plants,  being  found  in  croton, 
curcas,  etc.,  and  is  also  found  in  grape  seed.  Ricinoleic  acid  is 
soluble  in  alcohol  and  ether  and  is  insoluble  in  petroleum  ether.  It 
forms  crystalline  salts  with  barium,  calcium,  and  lead. 

JAPANIC  ACID  (C,2H42O4)  is  the  only  dibasic  acid  occurring 


A  TEXT-BOOK  OF  BOTANY. 

in  natural  fats,  and  is  found  in  Japan  wax.  The  crystals,  formed 
from  the  solutions  in  alcohol  or  chloroform,  are  heavier  than 
water. 

CHAULMOOGRIC  ACID  (C18H32O2)  occurs  as  a  glyceride  in 
chaulmoogra  oil,  being  obtained  from  the  seeds  of  Taraktogenos 
Kurzii  and  other  plants  of  the  Bixaceae.  It  has  the  composition 
of  linoleic  acid,  but  a  study  of  its  constitution  shows  that  it  is  in 
the  nature  of  a  cyclic  compound. 

The  following  alcohols  occur  as  esters  in  vegetable  waxes : 
Ceryl  alcohol  (C26H54O),  combined  with  palmitic  acid,  is  the 
principal  constituent  in  opium  wax.  Ceryl  alcohol  is  also  present 
in  carnauba  wax,  which  is  obtained  from  the  leaves  of  the  Car- 
nauba-palm  (Copernicia  cerifera).  Carnauba  wax  also  contains 
myricyl  or  melissyl  alcohol  (C30H62O),  the  latter  being  either 
free  or  combined  as  an  ester  of  cerotic  acid. 

PHYTOSTEROL,  a  compound  isomeric  with  cholesterol 
(C27H46O),  is  found  in  the  oils  derived  from  a  number  of  seeds. 
It  is  unsaponifiable,  and  is  found  in  the  extracted  oils  to  the  extent 
of  about  i  per  cent.  Phytosterol  crystallizes  in  the  monoclinic 
system  (Fig.  117),  whereas  cholesterol,  which  occurs  in  most  ani- 
mal oils  and  fats,  forms  triclinic  plates  resembling  rhombic  prisms 
(Bomer,  Zeits.  f.  Unter.  d.  Nahr-  u.  Genussmittel,  1898,  p.  42). 

LECITHIN  belongs  to  a  group  of  fatty  substances  containing 
nitrogen  and  phosphorus,  and  in  which  the  latter  is  present  as 
glycerophosphoric  acid.  They  are  sometimes  grouped  together 
in  a  special  class,  known  as  "  phosphatides,"  and  are  characterized 
by  containing  one  or  more  molecules  of  phosphoric  acid,  an  alcohol 
(as  glycerin),  one  or  more  fatty  acid  radicals  (as  stearic  or  oleic 
acid),  and  one  or  more  nitrogenous  bodies  (such  as  choline  and 
allied  substances).  Lecithin  occurs  in  seeds,  buds,  and  young 
shoots.  In  barley,  wheat,  and  rye  it  occurs  to  the  extent  of  0.6  per 
cent. ;  in  peas,  1.2  per  cent. ;  lupine  seeds,  2  per  cent. ;  mushrooms, 
0.9  per  cent. ;  dry  yeast,  2  per  cent.  (For  amount  in  other  plants 
see  Amer.  Jour.  Pharm.,  1914,  p.  169.)  According  to  Stoklasa,  the 
phosphoric  acid  of  plants  occurs  in  the  form  of  organic  com- 
pounds, of  which  lecithin  is  an  important  example.  It  is  formed 
in  those  organs  and  under  those  conditions  where  photosynthesis 
is  possible.  It  is  even  thought  that  lecithin  may  be  a  product 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       215 


of  assimilation  in  the  chloroplastid.  The  fact  that  fungi  con- 
tain it  shows  that  lecithin  may  be  formed  from  protoplasm  itself. 
It  is  one  of  the  most  interesting  compounds  which  has  been 
isolated  from  plants,  and  no  doubt  plays  an  important  role  in 
the  life  of  the  cell. 

Lecithin  is  a  yellow,  viscous,  waxy  substance  soluble  in  oils 

w 


FIG.  117.  Phytosterol  allowed  to  crystallize  very  slowly  from  strong  alcoholic  solu- 
tions, the  crystals  being  recrystallized  until  the  melting-point  is  constant.  I,  crystal  forms 
with  parallel  extinction  C  D.  II,  crystals  with  parallel  extinction  B  C.  Ill,  crystals  with 
parallel  extinction  along  the  long  axis.  IV,  common  crystal  forms  of  phytosterol.  Phytosterol 
is  a  constituent  of  most  vegetable  oils  and  is  most  abundant  in  peas,  lentils,  and  other 
Leguminous  seeds.  The  presence  of  vegetable  oils  is  detected  in  animal  oils  by  a  study 
of  the  forms  of  crystals,  those  of  phytosterol  crystallizing  in  the  monoclinic  system,  whereas 
cholesterol  forms  crystals  which  belong  to  the  triclinic  system. — After  A.  Bomer,  in  Zei'/s. 
/.  Unter.  d.  Nahr.-  u.  Genussmittel,  1898,  p.  45. 

and  warm  alcohol.  In  solutions  of  ether  or  chloroform  it  is  pre- 
cipitated upon  the  addition  of  acetone.  In  contact  with  water,  it 
separates  in  the  form  of  spiral  threads  or  loops,  giving  rise  to  the 
"  myelin  forms "  of  Kirchow  and  Beneke.  When  examined 
under  the  microscope  a  smear  of  lecithin,  to  which  a  drop  of 
water  or  a  sugar  solution  has  been  added,  sends  out  a  number  of 


216  A  TEXT-BOOK  OF  BOTANY. 

rounded  projections  which  gradually  elongate  and  become  more 
and  more  abundant  and  intricate.  If  this  process  be  allowed  to 
take  place  in  a  test-tube  or  other  vessel  that  can  be  shaken,  the 
water  becomes  turbid  through  the  dispersion  of  the  delicate 
microscopic  myelin  protrusions,  and  in  course  of  time  a  uniform 
emulsion  of  the  lecithin  in  water  is  obtained,  which  consists  of  fine 
swollen  particles.  This  is  a  colloidal  solution  that  can  be  filtered 
without  change.  It  is  not  coagulated  by  heat,  nor  precipitated  by 
salts  of  monobasic  or  tribasic  metals. 

WAX. — The  epidermal  layer  of  the  plant  shows  a  number  of 
modifications.  It  usually  consists  of  an  inner  layer  of  cellulose 
and  an  outer  covering  of  cutin.  While  some  of  the  lamellae  be- 
neath the  cutin  may  be  modified  to  mucilage  or  oil,  the  surface 
of  the  cutin  layer  may  have  deposited  upon  it  a  coating  of  'wax. 
Frequently  the  wax  is  in  such  small  quantities  that  it  is  not  ob- 
served until  the  sections  are  heated  to  a  temperature  of  90°  to 
100°  C,  when  the  wax  separates  in  the  form  of  oily  globules. 
According  to  De  Bary,  there  are  four  principal  forms  of  wax- 
coatings. 

i.  It  occurs  in  the  form  of  minute  rods  or  needles,  such  as  are 
found  constituting  the  bloom  of  fruits  as  the  grape  and  plum, 
and  the  stems  and  leaves  of  Eucalyptus  Globulus,  Ricinus  corn- 
munis,  etc.  2.  The  most  common  form  is  a  simple,  granular 
coating  consisting  of  isolated  grains  which  may  lie  together  as  a 
single  layer.  These  are  found  in  the  fruits  of  some  of  the 
Cruciferae,  Iris  pallida,  etc.  3.  The  coating  may  consist  of 
minute  rods  which  may  be  more  or  less  bent  or  curled,  standing 
perpendicularly  on  the  cuticle,  as  in  the  sugar  cane,  canna,  banana 
plant,  etc.  4.  The  wax  incrustation  may  occur  in  the  form  of 
membrane-like  layers,  varying  from  thin  scales,  as  in  Taxus 
baccata,  Portulaca  oleracea,  and  various  cacti,  to  thick  layers 
showing  a  striation  and  stratification  similar  to  that  found  in 
thick-walled  cells,  as  in  the  fruit  of  Myrica,  leaves  of  the  wax 
palm  (Ceroxylon  andicolum).  According  to  Wiesner,  the  deposit 
of  wax  is  often  crystalline,  appearing  in  four-sided  prisms.  (Con- 
sult A.  deBary,  "  Comparative  Anatomy  of  the  Organs  of 
Vegetation.") 

PHYSIOLOGY  OF  FATS. — It  is  stated  that  in  the  photosynthetic 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       217 

processes  of  some  of  the  lower  plants,  as  Vaucheria,  Diatoms,  etc., 
fixed  oils  rather  than  starch  are  formed  in  the  chromatophores. 
It  is  well  known  that  in  the  cells  of  the  bark  of  a  number  of  plants 
fixed  oils  are  stored  in  place  of  carbohydrates.  These  facts  show 
that  there  is  a  very  intimate  relationship  between  the  fixed  oils  and 
other  metabolic  substances.  Fixed  oils  constitute  the  reserve 
materials  in  seeds,  spores,  pollen  grains,  and  are  even  present  in 
the  tubers  of  certain  plants  as  Cyperus  esculentus.  The  storing 
of  fixed  oils  instead  of  starch  may  be  of  some  advantage  to  plants, 
in  that  there  is  a  greater  supply  of  energy  contained  in  them  than  is 
present  in  the  same  quantity  of  any  of  the  carbohydrates.  Again,, 
as  the  specific  gravity  of  the  fixed  oils  is  less  than  that  of  the  carbo- 
hydrates, this  is  an  advantage  in  those  spores  or  seeds  which  are 
disseminated  by  the  wind  and  require  to  be  as  light  as  possible. 

The  fixed  oils  are  more  or  less  intimately  associated  with  the 
protoplasm  occurring  in  vacuoles  of  the  same  in  fruits  and  seeds. 
The  waxes  which  are  secreted  in  the  epidermal  cells  of  leaves  and 
green  stems,  and  also  found  as  a  covering  of  many  fruits,  serve  to 
protect  the  underlying  cells  from  loss  or  excess  of  moisture, 
from  the  attack  of  disease-producing  micro-organisms,  and  also 
prevent  the  interactions  caused  by  some  of  their  enzymes.  The 
resistance  of  certain  micro-organisms,  as  the  tubercle-bacilli,  is 
supposed  to  be  due  to  some  extent  to  the  fatty  substances  in  which 
their  bodies  are  enclosed  or  with  which  they  are  impregnated. 
"  It  is  held  by  some  that  the  fats,  or,  more  correctly,  the  lecithin 
and  phospholipines,  are  essential  to  the  cohesion  and  physical 
constitution  of  the  protoplasm,  so  that  any  interference  with  the 
physical  state  of  these  substances  arrests  the  vital  functions.  The 
cement  which  binds  the  organized  matter  together  is  loosened  by 
the  solution  in  it  of  foreign  substances,  and  it  is  the  loosening 
of  the  protoplasmic  cement  that  makes  it  possible  for  the  normal 
processes  of  life  to  be  carried  on. 

"  Attempts  to  form  a  concrete  conception  of  the  physical  rela- 
tionship in  the  structural  organization  of  cells  between  fats  on  the 
one  hand  and  the  other  constituents  of  living  matter  on  the  other 
have  not  been  successful.  Some  have  spoken  of  '  lipoid  mem- 
branes '  as  if  the  living  cell  itself  were  enclosed  in  a  fatty  envelope 
and  accessible  only  to  such  substances  as  can  permeate  this  envelope 


218  A  TEXT-BOOK  OF  BOTANY. 

through  chemical  affinities  with  the  fatty  material  of  which  it  is 
composed.  Others  are  inclined  to  think  of  protoplasm  as  an 
emulsion  of  proteins  and  '  lipoids.'  Loeb  and  v.  Knaff  Lenz  find 
that  sea-urchin  eggs  are  liable  to  undergo  cytolysis  under  the 
action  of  any  process,  chemical  or  physical,  that  causes  the  cell 
fats  to  become  more  fluid."  (Consult  J.  B.  Leathes,  "The 
Fats.") 

Mucilages  and  Gums. — By  the  terms  mucilages  and  gums  are 
meant  those  substances  which  are  soluble  in  water,  or  swell  very 
perceptibly  in  it,  and  which,  upon  the  addition  of  alcohol,  are 
precipitated  in  the  form  of  a  more  or  less  amorphous  or  granular 
mass.  Mucilage  originates  in  the  plant  as  a  cell-content,  or  as  a 
modification  of  the  wall.  In  the  former  case  it  arises  as  a  product 
of  the  protoplasm,  or  it  may  be  a  disorganization  product  of  some 
of  the  carbohydrates.  When  it  arises  through  modification  of 
the  wall  it  is  spoken  of  as  "  membrane  mucilage,"  and  owes  its 
origin  to  several  causes :  either  to  a  secondary  thickening  of  or  an 
addition  to  the  cell  wall,  or  a  metamorphosis  of  it,  at  least  in  part. 
In  the  latter  case  it  may  arise  either  as  a  disorganization  product 
of  the  primary  wall,  or  of  the  subsequent  lamellae  making  up  the 
walls  of  the  cells  of  the  medullary  rays,  parenchyma,  and  other 
tissues,  as  in  Astragalus  gummifer  (Fig.  118),  or  it  may  arise 
as  an  intercellular  substance. 

The  following  is  a  classification  of  some  plants,  based  upon 
the  origin  of  the  mucilage: 

I.  Mucilage  in  the  form  of  a  cell-content  is.  of  infrequent 
occurrence  in  plants.  It  is  usually  present  in  the  cells  containing 
raphides,  especially  in  the  Monocotyledons.  Its  orgin  and  de- 
velopment may  be  easily  followed  in  the  tubers  of  a  number  ofj 
Orchids,  especially  those  yielding  salep.  The  mucilage  arises  very 
early  in  the  development  of  the  cells  surrounding  the  crystal- 
groups,  and  continues  to  be  formed  as  the  crystals  grow  in  size, 
the  protoplasm  and  nucleus  being  reduced  to  a  very  thin,  layer 
which  lie  next  to  the  cell-wall.  The  mucilage  of  salep  is  colored 
yellowish  with  iodine  and  sulphuric  acid,  or  a  yellowish-red  or 
rose-red  with  aqueous  eosin  solution,  and  a  carmine-red  with  an 
aqueous  solution  of  Congo  red.  The  cells  containing  mucilage  are 
easily  differentiated  from  the  surrounding  cells  by  the  use  of 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       219 

alcoholic  solutions  of  Congo  red,  methylene  blue,  etc.,  which  dis- 
tinctly color  the  mucilage  in  them.  Cell-content  mucilages  are  also 
found  in  the  fleshy  scales  of  the  onion,  the  rhizome  of  Agropyron 
repens,  the  fleshy  leaves  of  Aloe  and  other  succulent  plants.  It 


ms 


mst 


m 


FIG.  118.  Cross  section  through  pith  (m)  and  the  inner  portion  of  the  wood  (lt>)  of 
Astragalus  gummifer,  showing  successive  stages  in  the  modification  of  the  walls  in  the 
formation  of  gum  tragacanth  (o,  i,  2,  3,  4).  Some  of  the  tracheae  (c)  contain  globular 
masses  of  gum. — After  Tschirch. 

probably  also  occurs  in  this  form  in  the  Cyanophyceae  and  in 
some  of  the  red  algae,  as  Laminaria,  although  in  the  latter  it  is 
formed  chiefly  as  a  modification  of  a  cell-wall  and  the  intercellular 
substance.  In  Dicotyledons  the  mucilage  which  is  present  is 


220 


A  TEXT-BOOK  OF  BOTANY. 


usually  formed  as  a  modification  of  the  cell-wall,  and,  according 
to  Solereder,  it  seems  to  occur  in  the  contents  of  the  cell  in  only 
the  following  families :  CEnotheraceae.  Rubiaceae,  and  Vitaceae,  in 


FIG.  119.  Cell- wall  mucilage.  A,  transverse  section  of  seed-coat  of  flaxseed  treated 
with  water,  showing  the  swelling  of  the  mucilaginous  layer  situated  beneath  the  cutin; 
B,  section  of  Althaea  root  showing  three  large  mucilage-cells;  C,  transverse  section  of  elm 
bark  showing  four  large  mucilage-cells. 

all  of  which  the  mucilage  receptacles  can  be  interpreted  as  being 
incompletely  differentiated  raphide-sacs, — i.e.,  without  raphides. 
II.  Cell-membrane    mucilage, — i.e.,    mucilage    formed    as    a 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      221 

result  of  a  metamorphosis  of  the  cell-wall, — is  of  frequent  occur- 
rence, being  found  in  all  parts  of  the  plant,  including  the  endo- 
sperm cells  of  seeds,  parenchyma  cells  and  medullary  ray  cells  of 
roots  and  stems,  and  epidermal  cells  of  leaves,  stems,  fruits,  and 
seeds.  Cell-membrane  mucilage  is  also  found  in  some  of  the 
mucilaginous  marine  algae,  as  chondrus  laminaria,  etc.,  although 
in  the  latter  case  the  mucilage  is  often  spoken  of  as  being  derived 
from  the  intercellular  substance,  being  a  modification  of  the 


FIG.  120.  A,  B,  C,  successive  stages  in  the  development  of  the  mucilage  hairs  or  glands 
on  the  lobes  of  the  leaves  of  Viola  tricolor;  D,  young  secretion  hair  showing  some  of  the  cells 
with  large  nuclei  and  several  vacuoles;  E,  mature  hair;  F,  gland  showing  mucilaginous  layer 
beneath  the  cutin  and  the  protrusion  of  a  portion  of  the  mucilage  through  the  broken  wall; 
G,  portion  of  leaf  on  the  upper  part  of  the  lobes  of  which  occur  the  mucilage  glands. 

primary  wall.    It  may  also  occur  as  a  result  of  a  decomposition  of 
the  secondary  lamellae. 

Four  different  forms  of  mucilage  are  recognized.  I.  Mucilage 
cells,  or  distinct  cells  resembling  more  or  less  the  surrounding 
cells,  except  that  they  contain  mucilage,  occur  in  the  tissues  of 
leaves,  petals,  fruits,  seeds,  and  the  parenchyma  cells  of  pith 
and  primary  cortex  of  a  number  of  plants.  In  this  group  may  also 
be  included  the  gelatinized  cells  of  the  integumental  tissues 


222  A  TEXT-BOOK  OF  BOTANY. 

(epidermis  and  hypodermis),  as  these  in  many  cases  may  be 
mistaken,  as  in  the  Violaceae,  for  distinct  cells,  although  only  the 
inner  walls  of  the  epidermal  cells  are  gelatinized.  2.  Mucilage 
cavities  arise  from  the  simultaneous  gelatinization  in  the  walls 
of  a  group  of  cells.  These  are  found  in  the  cells  of  the  pith, 
cortex,  and  petioles  in  a,  number  of  plants  of  the  Malvaceae, 
Sterculiaceae,  Simarubaceae,  etc.  3.  Mucilage  canals  are  large 
cavities  formed  either  (A)  as  a  result  of  the  enlargement  of  the 
intercellular  spaces  between  the  cells,  the  primary  lamellae  being 
modified  to  mucilage;  or  (B)  are  formed  by  the  disintegration  or 
breaking  down  of  a  number  of  cells,  the  walls  of  which  become 
gelatinized.  In  the  former  case  they  are  spoken  of  as  "  schizog- 
enous  canals,"  and  in  the  latter  as  "  lysigenous  canals."  The 
latter  are  the  more  common  form  and  occur  in  the  pith  and 
primary  cortex  of  a  number  of  plants  belonging  to  the  Guttiferae, 
Malvaceae,  Sterculiaceae,  Oleaceae,  Rhamnaceae,  Vitaceae,  Legumi- 
nosae,  Rosaceae,  Cactaceae,  Piperaceae,  Moraceae,  and  Urticaceae. 
4.  Glandular  hairs  (Druzenzotten) .  In  this  form  (Fig.  118) 
they  are  found  in  the  lobes  of  the  leaves  and  calyces  of  Viola 
tricolor,  Coffea  arabica,  and  of  Prunus  avium. 

CHEMICAL  CLASSIFICATION  OF  MUCILAGE. — Mucilages  may 
be  distinguished,  according  to  their  behavior  with  special  reagents, 
as  cellulose-mucilages  or  pectose-mucilages.  The  former  are 
colored  blue  by  chlor-zinc-iodide,  and  are  soluble  in  ammoniacal 
solution  of  cupric  oxide.  To  this  class  belong  the  mucilages  of 
the  tuber  of  salep  and  the  seeds  of  cydonium.  The  pectose- 
mucilages  are  distinguished  by  the  fact  that  they  are  dissolved 
on  being  heated  with  solutions  containing  from  35  to  65  per  cent, 
cane  sugar.  They  are  also  stained  intensely  with  solutions  of 
saffranin,  methylene  blue,  .or  ruthenium  red. 

Mucilage  is  formed  in  large  quantities  in  certain  trees,  and  the 
exudation  which  is  collected  forms  the  so-called  gums  of  com- 
merce. As  these  are  largely  used  for  a  variety  of  technical  pur- 
poses, their  chemical  properties  have  been  studied,  so  that  four 
distinct  classes  of  gums  are  recognized. 

i.  Gums  containing  arabin  or  arabic  acid.  In  this  group  are 
included  gum  arabic,  obtained  from  Acacia  Senegal  and  other 
species  of  Acacia ;  Feronia  gum,  obtained  from  Feronia  elephan- 


CELL-CONTENTS  AND  FORMS  OF  CELLS       223 

turn    (Fam.   Rutaceae),   and   Anacardium  gum,   obtained    from 
Anacardium  occidentale. 

2.  Gums  consisting  of  mixtures  of  arabin  and  cerasin  (cerasic 
acid).    To  this  group  belong  the  exudations  formed  on  a  number 
of  trees  of  the  Rosaceae,  as  cherry,  almond,  apricot,  and  plum. 

3.  Gums  containing  bassorin.    Tragacanth  is  the  typical  gum 


FIG.  121.  Citrus  vulgaris.  Longitudinal  section  of  a  young  fresh  fruit  showing  a  lysig- 
enous  oil  canal  or  duct.  Se,  oil;  Zs,  cell  sap;  PI,  cells  in  which  the  walls  have  been  dis- 
solved; f,  thin-walled  cells;  D,  thick-walled  cells;  K,  nucleus;  Chr,  chromoplasts ;  o,  crystals 
of  calcium  oxalate;  e,  epidermis. — After  Meyer. 

of  this  class.  Included  in  this  group  are  a  few  other  gums  which 
find  some  commercial  use,  as  cocoa-palm  gum,  obtained  from  the 
bark  of  the  cocoa-nut  palm;  chagual  gum,  obtained  from  Puya 
coarctata  (Fam.  Bromeliacese),  and  Moringa  gum,  obtained  from 
Moringa  pterygosperma  (Fam.  Moringaceae). 

4.  Gums  containing  mixtures  of  cerasin  and  bassorin.     The 
East    Indian   gum,    obtained    from    Cochlospermum    Gossypium 


224 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  122.  Development  of  schizogenous  oleo-resin  canals  in  Brauneria  pallida.  A, 
intercellular  space  (o)  between  four  parenchyma  cells,  being  the  seat  of  the  early  formation 
of  the  canal  and  indicated  by  a  yellowish  oily  content.  B,  intercellular  oleo-resin  canal 
with  five  surrounding  parenchymatous  cells  (p).  C,  later  stage  of  canal  showing  separation 
of  small  oily  globules  in  the  intercellular  substance.  D  and  E,  the  intercellular  substance 
showing  an  almost  protoplasmic-like  structure,  some  of  the  lining  cells  being  developed  as 
papillae  and  suggesting  that  they  might  be  in  the  nature  of  secretion  cells,  although  it  is 
now  considered  that  the  oils  and  resins  of  this  character  are  formed  from  a  resinogenous 
layer  in  the  wall.  F,  longitudinal  section  showing  the  elongated  secretory  canal  between 
the  rows  of  cortical  parenchyma. 


CELL-CONTENTS  AND  FORMS  OF  CELLS       225 

(Fam.   Cochlospermaceae),   has   been   used  as   a   substitute  and 
adulterant  of  tragacanth. 

VOLATILE  OILS  AND  RESINS. — These  and  related  products, 
known  as  gum-resins  and  balsams,*  are  found  in  a  very  large 
number  of  plants.  Like  the  mucilages,  they  originate  either  as 
a  metamorphosis  of  the  cell-wall  or  as  a  direct  product  of  the 
protoplasm.  The  former  is  of  more  frequent  occurrence,  and  the 


B 


FIG.  123.  Development  of  a  lysigenous  secretory  canal  in  the  leaves  of  Dictamnus 
albus  (Fam.  Rutaceae).  The  development  begins  partly  in  the  cells  of  the  epidermal  layer 
and  partly  in  the  underlying  parenchyma  (A).  The  outer  cells  divide,  forming  the 
secretion  cells  (c),  while  the  inner  give  rise  to  the  reservoir  (B).  The  innermost  cells  then 
multiply  by  repeated  division  in  all  directions,  giving  rise  to  a  large  number  of  cells  containing 
globules  of  oil  (C).  Later  the  thin  walls  are  absorbed  and  the  oily  globules  fuse  together, 
forming  a  single  large  globule  (D). — After  Rauter. 

*  The  volatile  oils  are  not  infrequently  associated  with  other  sub- 
stances of  the  plant  cell  in  varying  proportions,  as  resin,  gums,  cinnamic 
and  benzoic  acids.  Those  products  which  consist  chiefly  of  oil  and  resin 
are  known  as  OLEO-RESINS,  and  include  turpentine  and  copaiba;  those 
consisting  chiefly  of  gum  and  resin  and  containing  but  little  volatile  oil 
are  known  as  GUM-RESINS,  and  include  ammoniac,  asafoetida,  galbanum, 
and  myrrh ;  oleo-resins  associated  with  aromatic  acids  are  known  as 
BALSAMS,  as  balsam  of  Tolu,  balsam  of  Peru,  storax,  and  benzoin,  which 
latter  is  usually  termed  a  balsamic  resin. 

15 


226  A  TEXT-BOOK  OF  BOTANY. 

layer  of  the  wall  in  which  the  decomposition  takes  place  has  been 
termed  by  Tschirch  a  resinogenous  layer. 

The  cells  or  receptacles  which  contain  oils,  resins,  gum-resins, 
and  balsams  are  usually  referred  to  as  "  secretory  cells "  or 
"  secretory  receptacles."  The  latter  term  is  used  by  Solejeder  to 
include  all  cells,  cell  fusions,  cavities  or  canals  which  are  filled 
with  secretions.  Usually  no  attempt  has  been  made  to  determine 
whether  the  secretion  is  a  volatile  oil  or  a  resin,  or  a  gum-resin 
or  a  balsam,  as  the  appearance  of  the  secretion  is  always  either 
in  the  form  of  globules  or  more  or  less  rounded  masses.  Secretory 
receptacles  may  arise  in  three  different  ways.  ( I )  As  a  modi- 
fication of  the  intercellular  substance  and  an  enlargement  of  the 
intercellular  areas,  giving  rise  to  schizogenous  receptacles  (Fig. 
122).  (2)  As  a  result  of  a  disintegration  of  a  group  of  cells 
and  a  decomposition  of  the  wall  substance,  forming  lysigenous 
receptacles  (Fig.,  123).  (3)  They  may  have  at.  the  outset  a 
schizogenous  origin,  but  later  the  surrounding  cells  in  addition 
break  down,  so  that  the  receptacle  is  more  properly  designated  as 
being  schizo-lysigenous.  In  certain  plants,  as  in  the  bark  of 
Sassafras  and  Cinnamon,  there  is  a  more  or  less  even  distribu- 
tion of  cells  in  the  cortex,  containing  volatile  oil,  on  the  one  hand, 
and  mucilage,  on  the  other.  Indeed,  it  is  supposed  that  the  cells 
giving  rise  to  mucilage  may  under  different  conditions  develop 
volatile  oil.  In  a  general  way  it  may  be  said  that  the  secretory 
receptacles  resemble  those  containing  mucilage,  both  as  to  the 
manner  in  which  they  originate  in  a  plant  and  the  physical  char- 
acters of  the  secretion.  Indeed,  they  may  be  closely  related  to 
the  mucilages  in  that  they  may  contain  a  large  proportion  of  gum, 
or  the  proportion  of  oleo-resin  and  gum  may  be  reversed. 

In  the  examination  of  technical  products,  and  especially  in 
taxonomic  work,  it  is  very  important  to  note  not  only  the  chemical 
character  of  the  secretions  but  also  the  fact  whether  the  cells  are 
isolated  or  whether  they  form  canals,  or  whether  the  secretory 
receptacle  is  only  a  cavity.  The  following  facts  may  be  given  in 
reference  to  the  four  principal  types  of  secretory  receptacles  : 

i.  Secretory  cells  are  distinct  cells  which  may  be  quite  dis- 
tinct from,  or  may  show  more  or  less  resemblance  to,  their 
neighboring  cells,  except  that  they  contain  oil  or  resin.  They 


CELL-CONTENTS  AND  FORMS  OF  CELLS/      227 

vary  in  length  and  outline,  being  either  spherical,  ellipsoidal,  sac- 
shaped  (Fam.  Bixaceae),  or  branched  (Fam.  Meliaceae).  The 
contents  may  be  in  the  form  of  distinct  globules  adhering  to  the 
wall  (or  in  dried  material  may  be  in  the  form  of -amorphous 
masses),  varying  in  color  from  colorless  to  yellowish  or  even  dark 
brown.  In  the  secretory  cells  of  certain  plants  of  the  Lauraceae, 
Magnoliaceae,  Canellaceae,  Aristolochiaceae,  and  Piperaceae  the 
secretory  contents  are  enveloped  by  a  thin-walled  sheath,  con- 
nected with  the  cell-wall  by  means  of  a  stalk.  The  internal  glandu- 
lar hairs  occurring  in  the  rhizome  of  Dryopteris  and  in  Pogoste- 
nwn  Patchouli  may  be  included  among  secretory  cells,  although 
they  project  into  the  intercellular  area  rather  than  into  the  cells. 
The  cell-wall  of  the  secretory  cells  not  infrequently  gives  a  dis- 
tinct reaction  for  suberin. 

Elongated  secretory  cells  or  sacs,  resembling  tannin-idioblasts, 
and  with  diverse  contents  varying  from  resin  to  latex-like  sub- 
stances or  tannin-like. masses,  are  distributed  in  the  cells  of  the 
pith,  bast,  and  pericycle  of  the  stem  and  occasionally  in  the  larger 
veins  of  the  leaves  of  some  of  the  genera  of  the  following  families  : 
Anacardiaceae,  Berberidaceae,  Caprifoliaceae,  Compositae,  Crassu- 
laceae,  Euphorbiacese,  Lecythidaceae,  Leguminosae  (very  widely 
distributed  and  with  diverse  contents),  Menispermaceae,  Monimi- 
aceae,  Myristicaceae,  Passifloriaceae,  Polygpnaceae,  Rosaceae,  and 
.Rubiaceas. 

Solereder  also  states  that  similar  elongated  sacs  with  brownish 
contents  are  observed  in  the  epidermal  cells  and  occasionally  in 
the  upper  layers  of  mesophyll  of  one  or  more  of  the  genera  in 
the  following  families :  Crassulaceae,  Euphorbiaceae,  Geraniaceae, 
Moraceae,  Saxifragaceae,  and  Violaceae. 

2.  Secretory  cavities  are  either  spherical  or  ellipsoidal  in  shape 
and  the  contents  vary  from  oily  or  resinous  to  gum-like  or  tannin- 
like  masses.  The  mode  of  development  of  the  cavities,  as  to 
whether  schizogenous,  etc.,  is  usually  not  considered,  as  this  fact 
is  not  easily  determined  in  the  mature  tissues.  When  occurring 
in  leaves  the  cavities  give  rise  to  transparent  dots  or  glandular 
punctate  areas.  They  are  also  found  in  the  pith  and  primary 
cortex  of  quite  a  number  of  plants. 

There  are  a  number  of  special  forms  of  secretory  cavities,  the 


228  A  TEXT-BOOK  OF  BOTANY. 

latter  in  some  cases  being  lined  by  a  papillose  epithelium  or  a 
form  of  bracket-cells,  etc.  They  are  found  in  the  following  fami- 
lies: Araliaceae,  Bixaceae,  Caesalpinaceae,  Compositae,  Connaracese 
(with  sphaero-crystalline  contents),  Euphorbiaceae  (with  bracket- 
epithelium),  Geraniaceae  (with  sphaero-crystalline  contents), 
Guttiferae,  Leguminosae  (intramural  glands  with  a  papillose  epi- 
thelium or  bracket-epithelium),  Lythraceae,  Malpighiaceae,  Mal- 
vaceae, Meliaceae,  Menispermaceae,  Myrtaceae,  Oleaceae,  Passi- 
floriaceae,  Piperaceae,  Podostemaceae,  Polygalaceae,  Polygonaceae 
(secretory  cavities  sometimes  formed  from  four  epidermal  cells), 
Primulaceae  (occasionally  with  red  crystalline  contents),  Pro- 
teaceae  (intramural  glands),  Rhamnaceae  (with  a  papillose  epi- 
thelium), Rosaceae,  Rubiaceae,  Rutaceae,  Simarubaceae,  Styracaceae, 
and  Theaceae. 

3.  Secretory  canals  differ  from  secretory  cavities  in  that  they 
are  more  or  less  elongated  receptacles  and  often  referred  to  as 
oil-ducts  or  oil-tubes.     Like  the  secretory  canals,  they  originate 
variously   and   have   diverse   contents.      They   may   occur   in   a 
number  of  different  portions  of  a  plant,  but  their  distribution  is 
quite  characteristic  of  certain  genera  or  even  of  families.    Secre- 
tory canals  have  been  observed  in  the  following  families :  Ana- 
cardiaceae,     Araliaceae,     Burseraceae,     Cactaceae,     Caesalpinaceae, 
Celastraceae,  Compositae,  Gesneraceae,  Guttiferae,  Hamamelidaceae, 
Leguminosae,   Pittosporaceae,  Podostemaceae,  Rhamnaceae,  Ruta- 
ceae, Simarubacese,  Theaceae,  and  Umbelliferae.     (Consult  Sole- 
reder's  "Systematic  Anatomy  of  the  Dicotyledons.") 

4.  Glandular   hairs.     Volatile   oils   and   resins   arise   in  the 
glandular  hairs   formed  on  the  surface  of   stems,  leaves,  and 
various  parts  of  the  flower  in  the  Labiatae,  Compositae,  and  other 
families.     In  these  hairs  a  volatile  oil  separates  in  the  form  of 
large,  oily  globules  which  lie  between  the  cuticle  and  the  outer 
wal]  of  the  underlying  cells  (Fig.  124).    The  origin  of  this  secre- 
tion has  been  variously  ascribed  to  the  protoplasmic  content  of  the 
cell  or  to  a  modification  of  the  cell-wall.    In  the  former  case  it  is 
said  to  arise  as  a  metabolic  substance  in  the  protoplasm,  and  is 
later  diffused  into  the  glandular  area  between  the  outer  cellulose 
wall  and  cuticle.     While  this  manner  of  formation  of  the  oily 
secretion  would  seem  reasonable,  yet  the  studies  by  Tschirch 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      229 

and  Tunmann  would  seem  to  show  that  the  secretion  in  the 
glandular  hair  arises  in  a  subcutaneous  layer  of  the  wall,  which  has 
been  termed  a  "  resinogenous  layer."  Even  De  Bary,  with  char- 
acteristic caution,  has  stated  that  the  secretion  found  in  the  walls 
of  glandular  hairs  originates  in  the  wall  even  though  the  ma- 
terials for  its  formation  must  arise  in  the  protoplasm  of  the  cells. 
In  the  study  of  glandular  hairs  the  method  of  Tunmann  may 
be  followed  (Ber.  d.  d.  pharm.  Gesellsch.,  1908',  p.  513).  Fresh, 
or  even  dried,  material  may  be  used.  Surface  sections  are  made 


FlG.  124.  A  glandular  hair  from  the  young  leaves  of  Lavandula  vera  seen  in  different 
stages  in  the  course  of  three  days,  showing  that  the  underlying  cells  remain  of  the  same 
size  and  structure,  but  that  there  is  a  gradual  increase  in  the  glandular  area  or  resinogenous 
layer. — After  Tunmann. 

and  examined  in  aqueous  solutions  containing  10,  20,  30,  or  40 
per  cent,  of  hydrated  chloral.  The  10  per  cent,  solution  is  used 
first,  then  the  20  per  cent.,  etc.  The  proper  solution  renders  the 
hair  transparent,  dissolves  the  resin,  and,  if  the  cover-glass  is 
moved  sidewise,  the  cuticle  bursts,  showing  the  resinogenous 
layer.  Tunmann  distinguishes  three  different  types  of  glandu- 
lar hairs,  depending  upon  the  character  of  this  resinog- 
enous layer,  (i)  In  which  by  this  treatment  there  separate 
small  rod-like  crystals  resembling  bacteria,  as  in  Fig.  125,  A,  B,  C. 
(2)  A  second  type  is  given  in  which  vacuoles  occur  consisting  of 


A  TEXT-BOOK  OF  BOTANY. 


rsg. 


PIG.  125.  Several  forms  of  glandular  hairs:  i.  In  which  the  resinogenous  layer  (rsg) 
separates  in  the  form  of  small  rods,  as  the  leaves  of  violets  (A),  Fraxinus  (B),  and  Alnus  (C). 
2.  The  resinogenous  layer  separating  in  the  form  of  vacuoles  in  the  hairs  of  Salvia  (D) 
and  Hyssopus  (E),  observed  in  the  dried  material  treated  with  dilute  solutions  of  hydrated 
chloral.  3.  A  lattice-like  or  cellular  resinogenous  layer  occurring  in  the  hairs  of  Rhodo- 
dendron (F)  and  Azalea  (G). — After  Tunmann. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       231 

a  fine  net-work,  as  in  Fig.  125,  D,  E.  (3)  A  third  type  in  which 
the  secretion  is  in  the  form  of  neither  rods  nor  vacuoles  but  a 
somewhat  cellular  structure,  termed  by  Tunmann  a  lattice-work. 
In  the  walls  of  the  glandular  hairs  other  substances  are  some- 
times present,  as  resins,  gums,  etc.  Hanstein  originally  pro- 
posed the  use  of  a  mixture  of  aniline  dyes  to  distinguish  resin, 
gum,  and  protoplasm  (Bot.  Zeit.,  1868,  p.  754),  but  later  studies 
have  shown  that  these  dyes  are  limited  in  differential  diagnosis 
of  many  of  these  substances.  The  cells  of  the  glandular  hairs 
may  contain,  in  addition  to  protoplasm,  protein  bodies,  chloro- 
phyll grains,  starch,  fixed  oil,  tannin,  calcium  oxalate,  reducing 
sugars,  and  other  special  substances,  which  are  colored  yellowish- 
red  with  solutions  of  the  alkalies  or  sulphuric  acid. 

MlCROCHEMISTRY  OF  THE  VOLATILE  OlLS  AND  RESINS. They 

are  readily  soluble  in  alcohol,  ether,  chloroform,  benzene,  acetic 
ether,  carbon  disulphide,  petroleum  ether,  etc.  They  are  also 
quite  soluble  in  glacial  acetic  acid  and  in  aqueous  solutions  of 
hydrated  chloral.  Some  of  them  are  soluble  in  dilute  alcohol. 
They  may  be  liberated  on  the  heating  of  sections  for  about  ten 
minutes  in  a  drying  oven  to  a  temperature  between  100°  and 
130°  C.  Like  the  fixed  oils,  they  are  colored  brownish  or 
brownish-black  with  osmic  acid  and  are  intensely  colored  with 
alkannin  and  cyanin.  The  volatile  oils  are  also  colored  a  carmine 
red  with  very  dilute  solutions  of  fuchsin.  Cells  containing  resins 
and  terpenes  are  colored  green  by  the  use  of  aqueous  solutions 
of  copper  acetate,  the  freshly  cut  twigs  or  leaves  being  allowed 
to  remain  in  the  solution  for  a  few  days. 

VOLATILE  OILS.— The  odors  which  are  characteristic  of 
very  many  plants  are  due  chiefly  to  a  group  of  principles  known 
as  volatile  oils.  They  are,  for  the  most  part,  mixtures  of  terpenes 
and  camphors,  and  are  obtained  from  the  plant  by  distillation 
with  steam,  the  oil  rising  to  the  surface  of  the  distillate,  being 
only  slightly  soluble  in  water.  Volatile  oils  are  readily  soluble 
in  alcohol,  ether,  chloroform,  and  in  the  fixed  oils.  Some  of 
them  show  a  tendency  to  absorb  oxygen,  and  are  converted  into 
resinous  substances.  They  are  widely  distributed  and  are  char- 
acteristic of  certain  families,  viz. :  Pinacese,  Cruciferae,  Labiatae, 
Lauracese,  Myrtacese,  Rutaceae,  and  Umbelliferae. 


232  A  TEXT-BOOK  OF  BOTANY. 

With  the  exception  of  the  seeds,  in  which  they  are  seldom 
found,  volatile  oils  occur  in  nearly  all  parts  of  the  plant.  They 
are  formed  either  as  a  direct  result  of  the  activities  of  the  pro- 
toplasm or  by  reason  of  changes  in  some  of  the  constituents  of 
the  cell-wall.  In  a  few  instances  the  volatile  oil  is  formed  from 
a  mother  substance,  being  in  the  nature  of  a  glucoside,  and  in  this 
form  occurs  in  the  seeds  of  the  almond  and  mustard. 

BOTANICAL  CLASSIFICATION. — The  composition  of  volatile 
oils  is  in  many  cases  very  complex ;  seldom  do  they  consist  of 
only  one  substance,  as  in  turpentine  oil.  Usually  they  consist  of 
a  number  of  chemical  compounds,  the  most  complex  being 
American  peppermint  oil,  from  which  no  less  than  seventeen 
different,  well-characterized  chemical  compounds  have  been 
isolated.  As  the  volatile  oils  are  of  considerable  economic  value, 
they  have  been  rather  very  extensively  studied.  It  remains  for 
botanists  to  apply  this  knowledge  to  the  study  of  the  living  plant. 
The  physiologist  will  find  the  study  of  the  origin,  transportation, 
and  localization  of  volatile  oils  in  different  parts  of  the  same 
plant  of  very  great  interest.  Such  studies  will  throw  considerable 
light  upon  the  entire  question  of  origin  and  transformation  of  the 
different  plant  constituents.  In  many  cases,  even  the  constitution 
of  the  constituents  in  volatile  oils  has  been  ascertained,  so  that 
on  a  sound  scientific  basis,  hypotheses  may  be  developed  con- 
cerning the  complex  changes  which  are  possible  in  the  substances 
derived  from  the  protoplasm.  Again,  the  distillation  products 
obtained  in  the  study  of  volatile  oil  show  that  the  living  plant 
may  contain  such  simple  compounds  as  formic  alcohol,  formalde- 
hyde, formic  acid,  hydrocyanic  acid,  etc. 

Volatile  oils  which  have  been  carefully  studied  are  obtained 
from  plants  of  the  following  families:  Polypodiaceae,  Pinaceae, 
Pandanaceae,  Gramineae,  Palmae,  Araceae,  Liliaceae,  Iridaceae,  Zingi- 
beraceae,  Piperaceae,  Salicaceae,  Myricaceae,  Juglandaceae,  Betu- 
laceae,  Moraceae,  Aristolochiaceae,  Chenopodiaceae,  Ranunculaceae, 
Magnoliaceae,  Anonaceae,  Myristicacese,  Monimiaceae,  Lauraceae, 
Cruciferae,  Resedaceae,  Hamamelidaceae,  Rosaceae,  Leguminosae, 
Geraniaceae,  Tropaeolaceae,  Erythroxylaceae,  Zygophyllaceae, 
Rutaceae,  Burseraceae,  Meliaceae,  Polygalaceae,  Euphorbiaceae, 
Anacardiaceae,  Vitaceae,  Tiliaceae,  Malvaceae,  Theaceae,  Diptero- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       233 

carpaceae,  Cistaceae,  Turneraceae,  Lythraceae,  Myrtaceae,  Aralia- 
cese,  Umbelliferae,  Ericaceae,  Primulaceae,  Convolvulaceae,  Ver- 
benaceae,  Labiatae,  Solanaceae,  Caprifoliaceae,  Valerianaceae,  and 
Compositae. 

COMPOSITION  OF  VOLATILE  OILS. — The  volatile  oils  are  usu- 
ally of  a  very  complex  composition;  it  will  be  found,  however, 
that  they  owe  their  principal  characteristics  to  one  or  more 
definite  compounds.  The  following  classes  of  compounds  have 
been  derived  from  the  volatile  oils. 

TERPENES,  hydrocarbons  of  the  formula  C10H16,  are  found  in 
the  volatile  oils  of  the  Pinaceae,  Rutaceae,  etc.  The  terpene  pinene 
makes  up  practically  the  entire  bulk  of  turpentine  oil.  The 
terpene  limonene  is  found  in  the  oil  of  lemon  to  the  extent  of 
90  per  cent.  It  is  not,  however,  the  characteristic  constituent  in 
this  oil,  the  odor  of  lemon  being  due  to  an  aldehyde,  citral. 

SESQUITERPENES,  hydrocarbons  of  the  formula  C15H24,  have 
been  isolated  from  a  number  of  oils,  the  best  known  representa- 
tive of  this  class  being  cadinene,  occurring  in  the  oils  of  cubeb, 
patchouli,  savin,  etc. 

ALCOHOLS  belonging  to  the  aliphatic  and  aromatic  series  occur 
in  a  number  of  oils  combined  as  esters  with  the  fatty  acids.  Both 
methyl  alcohol  and  ethyl  alcohol  are  found  in  the  aqueous  dis- 
tillates in  the  preparation  of  certain  oils.  This  occurrence  is 
usually  explained  as  being  due  to  the  decomposition  of  other  sub- 
stances. Methyl  alcohol  is  thought  to  be  derived  from  the  de- 
composition of  cellulose,  while  ethyl  alcohol  is  considered  to  be 
a  product  of  the  fermentation  of  carbohydrates.  That  ethyl 
alcohol  may  be  derived  in  this  manner  is  probable  from  the  obser- 
vations of  Maze,  who  obtained  alcohol  from  germinating  seeds. 
Esters  of  methyl  alcohol,  especially  methyl  salicylate,  are  widely 
distributed.  Among  other  alcohols,  the  following  may  be  men- 
tioned: Linalool  constitutes  the  bulk  of  lignaloe  oil;  geraniol,  a 
diolefinic  alcohol  makes  up  the  bulk  of  rose  oil ;  benzyl  alcohol, 
as  an  ester,  occurs  in  the  oils  of  jasmine,  tuberose,  ylang-ylang, 
etc. ;  cinnamic  alcohol,  as  an  ester,  occurs  in  cassia  oil,  storax,  and 
Peru  balsam ;  menthol  (peppermint  camphor),  a  secondary  alcohol, 
is  found  in  peppermint  oil;  borneol  (camphyl  alcohol)  occurs 


234  A  TEXT-BOOK  OF  BOTANY. 

in  the  oils  of  valerian  and  serpentaria,  the  acetate  of  this  alcohol 
being  found  in  many  oils  of  the  Pinacese. 

ALDEHYDES. — The  simplest  of  the  aliphatic  aldehydes,  for- 
maldehyde, has  been  found  in  apopin  oil,  the  latter  being  derived 
from  an  unknown  plant  growing  in  Japan.  Acetaldehyde  is  com- 
monly present  in  the  distillates  of  seeds.  Citral  is  found  in 
lemon  oil,  giving  it  its  characteristic  odor.  It  is  also  found  in  the 
oils  distilled  from  the  leaves  and  twigs  of  the  lemon  tree,  sweet 
orange  tree,  sassafras,  etc.  Benzaldehyde  is  formed  upon  the 
hydrolysis  of  amygdalin. 

KETONES. — Of  the  aliphatic  ketones,  acetone  has  been  ob- 
served, together  with  hydrocyanic  acid,  in  the  distillation  of  a 
number  of  leaf  oils.  Carvone  occurs  in  the  oil  of  caraway. 
Pulegone  occurs  in  large  amounts  in  European  pennyroyal 
oil  and  the  oils  of  other  members  of  the  Labiate.  Japanese  or 
laurel  camphor  is  obtained  by  the  distillation  of  the  wood  of 
Cinnamomum  Camphora.  Irone,  a  cyclic  ketone,  occurs  in  orris 
root. 

PHENOLS  AND  PHENOL  ETHERS  are  found  in  a  number  of 
volatile  oils.  Thymol  constitutes  the  larger  part  of  the  oil  of 
ajowan  (Ptychotis  coptica).  Carvacol  is  a  constituent  in  many 
Labiate  oils.  Anethol  is  the  principal  constituent  of  the  oils 
of  Pinipinella  anisatum  and  Illicium  verum  and  is  an  important 
constituent  in  the  oil  of  fennel.  Eugenol  occurs  in  the  oils 
of  the  Myrtacecc  and  Lauracecc.  Apiol  is  a  constituent  o<f  the 
fruit  of  parsley,  and  safrol  is  the  principal  constituent  of 
sassafras  oil. 

ACIDS. — Quite  a  number  of  acids  are  obtained  as  a  by-product 
in  the  aqueous  distillation  of  volatile  oils.  Among  these  may  be 
mentioned  formic  acid,  acetic  acid,  isovaleric  acid,  benzoic  acid, 
cinnamic  acid,  salicylic  acid,  etc. 

ESTERS  give  the  fragrance  to  most  volatile  oils.  Some  oils 
consist  almost  entirely  of  esters,  as  wintergreen  oil  and  birch 
oil,  which  contain  methyl  salicylate.  The  latter  is  probably  one 
of  the  most  widely  distributed  of  the  esters.  Linalyl  acetate  is 
the  characteristic  constituent  of  bergamot  and  lavender  oils. 
Geranyl  acetate  is  found  in  the  oils  of  lemon  grass,  neroli, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      235 

coriander,  etc.  Esters  of  benzoic  and  cinnamic  acids  are  found 
in  storax,  Tolu  balsam,  and  Peru  balsam.  Bornyl  isovalerate 
occurs  in  valerian  oil. 

LACTONES. — The  odoriferous  principle  known  as  coumarin  is 
widely  distributed  in  the  plant  kingdom.  It  occurs  in  some  of 
the  ferns,"  grasses,  tonka  bean,  "  Waldmeister "  (Asperula 
odorata),  etc.  It  apparently  is  formed  as  the  result  of  the  action 
of  a  ferment,  as  it  is  detected  only  after  the  drying  of  the  plant. 
Alantolactone  is  the  principal  constituent  of  the  oil  of  Inula 
Helenium. 

NITROGEN  AND  SULPHUR  COMPOUNDS  occur  frequently  in  the 
aqueous  distillates  of  plants  yielding  volatile  oils.  Hydrocyanic 
acid  is  readily  detected  by  means  of  Prussian  blue,  and  occurs  in 
the  distillates  not  only  of  cyanogenetic  plants  but  in  a  large  num- 
ber of  others  as  well.  The  mustard  oils  are  esters  of  isothio- 
cyanic  acid  and  are  characterized  by  their  penetrating  odors. 
Allyl  mustard  oil  is  obtained  from  the  seeds  of  Sinapis  nigra  and 
a  few  other  plants  of  the  Cruci ferae.  (Consult  "  The  Volatile 
Oils,"  Gildemeister  and  Hoffman,  translation  by  Edward 
Kremers;  also  "  Semiannual  Reports,"  by  Schimmel  &  Co.) 

FORMATION  OF  VOLATILE  OILS. — The  chemical  study  of 
odorous  principles  shows  that  they  vary  considerably  in  their* 
composition.  Not  much  is  known  regarding  the  formation  of 
volatile  oils.  Charabot  and  Herbert  have  suggested  that  the  esters 
may  originate  in  the  cells  containing  chloroplastids.  They  suggest 
that  under  the  influence  of  an  enzyme  of  reversible  activity  the 
esters  are  formed  from  the  acids  and  alcohols  present  in  the  plant 
cell,  and  that  they  continue  to  form  until  the  flowering  period. 
They  are  then  diffused  to  other  parts  of  the  plant,  notably 
the  inflorescence.  While  some  of  the  oils  are  indirect  products 
connected  with  photosynthesis,  others  arise  through  the  decom- 
position of  a  mother  substance,  as  the  glucosides,  and  still  others 
originate  as  a  metamorphosis  of  the  cell-wall. 

PHYSIOLOGICAL  ROLE  OF  OILS. — It  is  usually  considered  that 
volatile  oils  occurring  in  receptacles  near  the  surface  of  the  plant, 
as  in  fruits  like  the  orange,  serve  to  prevent  the  entrance  of 
animal  and  vegetable  parasites,  and  thus  prevent  disease.  Again, 
the  oils  which  are  found  in  glandular  hairs  covering  the  leaves 


236  A  TEXT-BOOK  OF  BOTANY. 

and  stems  of  many  plants  are  supposed  to  be  useful  in  preventing 
depredations  by  animals.  The  odorous  principles  which  occur  in 
many  flowers  are  supposed  to  exert  a  directive  influence  upon 
insects  and  thus  assist  in  the  work  of  cross-pollination.  While 
biologists  usually  consider  the  volatile  oils  as  serving  ecological 
uses  yet  those  investigators,  who  study  the  perfume-yielding  con- 
stituents very  closely,  are  inclined  to  consider  them  as  being  in  the 
nature  of  food  materials  that  are  used  after  the  fertilization  of  the 
flower  and  during  the  development  of  fruit  and  seeds. 

RESINS,  GUM-RESINS  AND  BALSAMS. — A  large  number  of  this 
class  of  plant  products  are  found  in  commerce  and  used  in  medi- 
cine and  in  the  arts.  A  few  of  these  occur  as  normal  products 


FIG.  126.     Menthol:  A,  individual  crystals  obtained  by  sublimation;  B,  the  commonly 
occurring  aggregates  of  very  fine  needles. 

in  living  plants,  as  the  gum-resins  of  the  Umbelliferse,  the  gum- 
resin  euphorbium,  and  the  resins  of  mastiche  and  sandarac.  Most 
of  the  others  arise  as  a  result  of  wounds  in  plants  and  are  in  the 
nature  of  pathological  products,  as  benzoin,  styrax,  Tolu  balsam, 
Peru  balsam,  etc.  Until  recently  not  much  was  known  except  in  a 
general  way  regarding  the  composition  of  resins.  Largely  through 
the  researches  of  Tschirch  and  his  students  the  nature  and  the 
constitution  of  the  important  constituents  in  a  number  of  the 
resins  have  been  worked  out.  As  a  result  of  these  studies  seven 
principal  groups  of  resins  are  recognized. 

I.  Tannol  Resins. — These  are  esters  of  aromatic  phenols  and 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      237 

behave  toward  iron  salts  and  some  other  reagents  like  tannin. 
They  are  found  in  relatively  large  amounts  in  a  number  of  the 
resins  and  balsams,  and  occur  in  rather  widely  separated  families, 
as  follows :  Peru  balsam  and  Tolu  balsam  obtained  from  certain 
members  of  the  Leguminosae,  styrax  from  the  Hamamelidacese, 
benzoin  from  the  Styracaceae,  aloe  from  the  Liliaceae,  dragon's 
blood  from  the  Palmae,  and  the  resins  from  the  Umbelliferae,  in- 
cluding ammoniac,  galbanum,  asafoetida,  etc. 

2.  Resene   Resins. — These   are   mostly   colorless,   indifferent 
substances   occurring   in   resins   and   are   not   only   insoluble   in 
potassium  hydroxide  but  exceedingly  resistant  to-  it,  and  are  not 
capable   of   acetylization.      To   this   group  belong  the   resinous 
exudations  of  the  Burseraceae,  including  myrrh,  olibanum,  and 
elemi;  also  of  the  Anacardiaceae,  including  mastic;  and  of  the 
Dipterocarpaceae,  including  gurjun  balsam  and  dammar. 

3.  Resinolic  Acid  Resins. — These  are   oxy-acids   containing 
either  or  both  hydroxyl  and  carboxyl  groups.    They  form  color- 
less crystals  and  are  either  free  or  combined  with  alcohol  in  the 
form  of  esters.     They  have  an  acid  reaction  and  are  soluble  in 
solutions  of  sodium  hydroxide,  and  with  difficulty   form  com- 
pounds with  acetyl  chloride.    Acids  belonging  to  this  group  have 
been  obtained  from  a  number  of  the  resinous  exudations  of  the 
Coniferae,   including   sandarac,   Canada   turpentine,   and   Strass- 
burg  turpentine.     It  is  also  obtained  from,  a  number  of  resins 
which  are  in  the  nature  of  pathological  products,  as  larch  turpen- 
tine, Jura  turpentine,  and  French  turpentine.     The  abietic  acid 
in  colophony  and  the  succinoabietic  acid  found  in  the  fossil  resin 
known  as  amber,  also  belong  to  this  class  of  acids.    Furthermore, 
resinolic  acids  are  found  in  the  fungus  Polyporus  officinalis,  and 
in  some  of  the  exudations  of  the  Leguminosae,  including  the  oleo- 
resin  known  as  copaiba  and  the  recent- fossil  resin,  Zanzibar- 
copal. 

4.  Resinol   Resins. — Resinols    are   aromatic    alcohols    which 
usually  form  colorless  crystals  and  occur  either  free  or  in  the 
form  of  esters.    The  principal  constituents  of  guaiac  resin  belong 
to     this     class,     namely,     guaiaconresinol     (guaiaconic     acid), 
guaiacresinol    (guaiacic   acid),   and   guaiacinresinol    (guaiacinic 
acid).    Resinols  are  also  found  in  small  quantities  in  other  resins. 


238  A  TEXT-BOOK  OF  BOTANY. 

5.  Fatty-resins. — The  resins  of  this  class  differ  from  the  others 
heretofore  considered  in  that  they  are  derivatives  of  some  of  the 
fatty  acids.    To  this  group  belongs  the  resinous  exudation  known 
as  "  stick-lac,"  occurring  on  a  number  of  trees  growing  in  the 
East  Indies,  being  caused  by  the  punctures  of  a  hemipterous  in- 
sect,  Coccus  lacca. 

6.  Pigment  Resins. — In  this  group  are  included  those  exuda- 
tions in  which  the  resins  are  combined  with  a  chromogenic  deriva- 
tive.   These  have  been  studied  but  very  little,  and  the  best  repre- 
sentative of  this  class  is  gamboge,  which  is  used  in  medicine  as 
well  as  for  coloring  in  art. 

7.  Glucosidal   Resins. — This    group    includes,    as    the    name 
would  imply,  those  resins  which  are  in  the  nature  of  glucosides 
and  yield  on  hydrolysis  glucose  as  well  as  some  other  derivative. 
The  resins  found  in  jalap,  scammony,  and  other  plants  of  the 
Convolvulaceae  belong  to  this  group.     (Consult  A.  Tschirch,  "  Die 
Harze  und  die  Harzbehalter.") 

ORIGIN  OF  RESINS. — It  was  at  one  time  considered  that  the 
resins  were  derivatives  of  tannin.  Now  that  Tschirch  has  shown 
that  there  are  a  class  of  resinous  substances  that  give  reactions 
for  tannin,  it  might  seem  that  this  theory  would  receive  additional 
support.  However,  as  he  himself  explains,  the  resinotannols  con- 
tain a  great  deal  more  carbon  than  the  tannins.  Furthermore, 
Tschirch  has  shown  that  a  number  of  the  constituents  of  the 
resins  give  color  reactions  with  Liebermann's  reagent  for  phy- 
tosterol.  On  the  other  hand,  a  number  of  these  same  constituents 
do  not  give  the  characteristic  color  reaction  for  phytosterol  with 
Salkowsky-hesse's  reagent.  With  regard  to  the  resins  of  the 
resinolic  acid  series,  Tschirch  concludes  that  they  are  probably 
not  derived  from  volatile  oils,  but  that  they  are  derivatives  of  a 
common  mother  substance.  In  a  later  publication  Tschirch 
("  Chemie  und  Biologic  der  Pflanzlichen  Sekrete  ")  states  that  in 
all  probability  all  the  secretory  products,  formed  as  a  meta- 
morphosis or  decomposition  of  the  resinogenous  lamellae,  are  the 
direct  products  of  ferments  accompanying  these  layers. 

LATEX  OR  MILK- JUICE  is  the  product  formed  in  special  secre- 
tory organs  in  the  plant,  and  exudes  readily  on  even  very  slight 
injury  of  the  plant.  Under  the  microscope  it  is  seen  to  be  in 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       239 

the  nature  of  an  emulsion,  consisting  of  small  globules,  varying 
from  0.0005  to  0.005  mm.  in  diameter.  It  is  of  variable  com- 
position and  may  contain  certain  hydrocarbons,  as  in  pure 
caoutchouc  and  pure  gutta  percha,  oils,  resins,  mucilage,  starch, 
calcium  oxalate,  and  alkaloids. 

Latex  is  found  in  three  distinct  types  of  tissues,   differing 


FIG.  127.  Study  of  Latex:  A,  tangential-longitudinal  section  through  root  of  Taraxa- 
cum, showing  laticiferous  vessel  (m),  sieve  tube  (s),  parenchyma  (p).  B,  the  bark  of 
Euonymus,  fractured  and  showing  the  thread-like  latex  (c)  between  the  pieces  (b).  C,  the 
fragments  of  thread-like  latex  of  Euonymus  viewed  under  the  microscope,  and  distinguished 
from  fibers  by  their  dissolving  in  chloroform. — A,  after  Meyer;  C,  from  drawing  by  Hogstad. 

from  each  other  in  origin  and  manner  of  development,  i.  Laticif- 
erous cells  are  long,  tubular  cells  which  arise  in  the  initial  cells 
of  the  embryo  and  continue  to  elongate,  keeping  pace  with  the 
growth  of  the  plant,  branching  and  traversing  all  of  its  organs. 
They  may  extend  through  the  cells  of  the  pith,  bast,  and  primary 
cortex,  run  along  the  veins  of  the  leaf,  being  found  occasionally 
in  the  mesophyll,  and  extend  into  the  fruit.  Cells  of  this  kind 


240 


A  TEXT-BOOK  OF  BOTANY. 


are  present  in  the  Apocynaceae,  Asclepiadaceae,  Euphorbiaceae, 
Moraceae,  and  Urticaceae.  2.  Laticiferous  vessels  are  long  tubes 
resembling  the  latex  cells,  but  are  formed  by  the  absorption  of  the 
transverse  walls  in  the  superimposed  cells.  They  develop  very 
early,  the  cell-fusions  taking  place,  in  some  instances,  in  the 
primary  meristems.  They  may  be  either  simple  or  branching,  the 
branches  connecting  with  other  tubes  and  forming  a  net-work. 
These  anastomosing  tubes  can  be  separated  readily  from  the  sur- 


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FIG.  128.  Microscopical  appearance  of  latex  in  Ficus  elastica,  showing  small  globules 
and  sphere-crystals  which  separate  soon  after  the  removal  of  the  fresh  latex. — From  a  draw- 
ing by  Hogstad. 

rounding  tissues  by  boiling  the  material  with  dilute  solutions  of 
potassium  hydroxide.  The  laticiferous  vessels  usually  occur  as- 
sociated with  the  leptome,  although  they  may  be  found  in  other 
tissues  of  the  axis  and  leaf.  Milk  vessels  are  found  in  the  fol- 
lowing families :  Araceae,  Campanulaceae,  Compositae,  Convol- 
vulaceae,  Euphorbiaceae,  Geraniaceae,  Musaceae,  Oleaceae,  and 
Papaveraceae.  3.  Secretory  cells  resembling  laticiferous  cells, 
in  that  they  have  a  latex-like  content,  although  probably  of 
secondary  origin,  have  been  found  in  the  Celastraceae,  Oleaceae, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       241 

Tiliacese,  and  Urticacese.  The  secretion  in  these  cells  is  some- 
times visible  even  with  the  naked  eye,  and  it  is  possible,  on  break- 
ing the  bark,  to  obtain  the  latex  in  the  form  of  delicate,  elastic 
threads.  These  caoutchouc  threads  may  be  readily  seen  on  break- 
ing the  bark  of  euonymus,  and  may  be  distinguished  from  bast- 
fibers  by  their  readily  dissolving  in  chloroform  (Fig.  127). 

The  milk-juice  varies  in  color  in  different  plants,  being  color- 
less, as  in  oleander ;  whitish,  as  in  the  Apocynaceae  and  Asclepiada- 
ceae;  or  yellowish,  as  in  chelidonium,  or  orange-red,  as  in 
sanguinaria.  The  latex  of  a  number  of  plants  is  collected  to  form 
a  number  of  commercial  products.  Opium  is  the  dried  milk-juice 
obtained  from  the  capsules  of  Papaver  somniferum.  Lactucarium 
is  the  dried  milk-juice  of  Lactuca  virosa  and  other  species  of 
Lactuca.  Elastica  or  India  rubber  is  the  prepared  milk- juice  ob-i 
tained  from  a  number  of  plants,  the  most  important  being  the 
Brazilian  or  Para  rubber  tree  (Hevea  brasiliensis) ,  the  Central 
American  rubber  tree  (Castilloa  elastica),  the  East  Indian  rubber 
tree  (Ficus  elastica),  and  the  rubber  vines  of  Africa  (Landolphia 
species).  Gutta  percha  is  the  concrete  juice  of  Palaquium  Gutta 
(Fam.  Sapotaceae). 

ENZYMES  OR  FERMENTS. — In  connection  with  the  growth  of 
the  plant,  there  occurs  a  constant  change  in  the  substances  which 
comprise  it.  These  changes  are  brought  about  largely  through 
the  influence  of  a  class  of  substances  known  as  enzymes.  Atten- 
tion has  been  directed  to  the  decomposition  of  starch  with  the 
formation  of  sugar.  This  change  is  brought  about  by  the  secre- 
tion in  the  protoplasm  of  an  enzyme  called  amylase  (diastase). 
It  is  produced  in  the  living  cell,  can  be  extracted  from  the  plant, 
and  will  produce  the  same  effect  upon  starch  grains  which  have 
been  separated  from  the  cells. 

One  of  the  interesting  properties  of  the  ferments  is  that  in' 
comparison  with  the  amount  of  ferment  employed  the  product 
formed  through  its  influence  is  very  large.  Thus  it  is  stated  that 
amylase  is  able  to  hydrolyze  10,000  times  its  own  bulk  of  starch. 
Results  of  this  kind  are  considered  to  be  due  to  catalytic  action 
of  the  ferments,  i.e.,  their  power  of  inducing  chemical  reactions 
by  their  mere  presence  without  themselves  entering  into  the 
products  formed.  The  ferments  require  specific  temperatures  for 
16 


242  A  TEXT-BOOK  OF  BOTANY. 

their  action,  as,  for  example,  emulsin  or  sinaptase,  which  decom- 
poses a  number  of  the  glucosides  at  a  temperature  of  35°  to  40° 
C.,  while  amylase,  the  ferment  of  germinating  seeds,  requires  a 
somewhat  higher  temperature,  namely,  50°  to  70°  C. 

Another  property  of  these  ferments,  which  is  generally  re- 
garded as  characteristic  of  them,  is  that  of  becoming  inactive  when 
solutions  are  heated  to  a  temperature  of  100°  C.  Nothing  is 
known  with  regard  to  the  composition  and  constitution  of  the 
ferments,  and  they  are  usually  classified  according  to  the  class 
of  substances  which  they  decompose.  Thus,  amylases  act  upon 
starch  grains  with  the  formation  of  sugar;  proteinases  break 
down  the  true  proteins,  etc. 

The  following  is  an  enumeration  ot  the  principal  plant 
enzymes,  together  with  their  occurrence  and  some  of  their 
properties : 

AMYLASE. — The  ferment  acting  upon  starch  in  germinating 
barley,  with  the  formation  of  glucose  and  maltose,  was  separated 
by  Payen  and  Persoz  in  1833,  and  called  "  diastase."  This  fer- 
ment occurs,  probably,  in  all  parts  of  all  green  plants,  and  is 
especially  abundant  in  all  cells  where  starch  is  formed  OT  stored. 
It  is  found  in  large  amounts  in  various  cereal  grains,  and  also 
occurs  in  the  fungi,  yeasts,  and  bacteria.  Recent  investigation 
seems  to  show  that  in  the  cells  with  reserve  starches  there  are  two 
different  kinds  of  diastatic  enzymes,  the  one  acting  on  the  soluble 
starch,  called  amylase,  and  the  other  acting  on  the  insoluble 
starch  or  amylopectin,  and  called  amylopectinase. 

INULINASE  is  the  ferment  found  in  the  cells  of  plants  contain- 
ing inulin.  It  decomposes  the  latter,  changing  it  into  fruit  sugar 
or  fructose.  Inulinase  has  no  effect  upon  starch.  It  has  been 
found  in  the  Composite  and  also  in  Aspergillus,  Penicillium, 
and  a  number  of  genera  of  the  Eumycetes. 

MALTASE  (a-glucosidase)  is  always  associated  with  the 
diastases,  and  from  which  it  has  not  been  separated.  It  is  widely 
found  in  the  vegetable  kingdom,  and  is  especially  abundant  in 
malt  and  some  of  the  yeasts. 

INVERTASE  (a-fructosidase),  sometimes  also  spoken  of  as  in- 
vertin  or  sucrose,  has  the  property  of  converting  cane  sugar  into 
invert  sugar  (a  mixture  of  glucose  and  fructose).  It  is  found  in 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       243 

wheat  and  barley,  dates,  bananas,  mulberries,  and  especially  in 
the  green  leaves  and  young  shoots  of  higher  plants.  In  yeast  it 
is  accompanied  in  many  cases  by  maltase. 

EMULSINS  are  a  class  of  glucoside-resolving  enzymes  found 
in  the  seeds  of  the  almond,  the  bark  of  Prunus  serotina,  the  leaves 
of  Prunus  Laurocerasus,  and  in  a  large  number  of  plants  of  the 
Rosacese.  It  is  also  found  in  the  tuberous  roots  of  Manihot 
utilissima,  Monotropa,  species  of  Polygala,  Hedera  Helix. 
Enzymes  resembling  emulsins,  and  capable  of  attacking  gluco- 
sides,  have  been  detected  also  in  Aspergillus,  several  species  of 
Polyporus,  found  growing  in  wood,  lichens,  mosses,  and  bacteria. 
A  distinction  is  sometimes  made  between  almond-emulsin,  Asper- 
gillus-emulsin,  etc. 

MYROSIN,  an  enzyme  which  hydrolyzes  the  sulphur-glucosides, 
occurs  in  the  Cruci ferae  and  in  certain  species  o-f  Manihot.  It  is 
localized  in  the  seeds  of  cells  which  are  rich  in  proteins.  Its 
presence  may  also  be  demonstrated  in  the  mesophyll  of  young 
leaves,  in  the  pericycle  of  stems,  and  in  the  cork-cells  of  roots. 

GAULTHERASE  (Betulase),  an  enzyme  which  hydrolyzes  the 
glucoside  of  methyl  salicylate  called  "  Gaultherin."  This  is 
present  in  Gaultheria  and  many  other  of  the  Ericaceae.  It  is 
probably  very  widely  distributed  in  the  vegetable  kingdom.  (See 
Amer.  Jour.  Pharm.,  1898,  p.  412.) 

PECTASE  AND  PECTINASE. — The  name  Pectase  is  applied  to  an 
enzyme  that  is  always  present  in  ripening  fruit,  and  is  capable 
of  converting  pectose,  a  product  insoluble  in  water,  into  a  soluble 
substance  called  pectin.  The  latter  can  be  further  decomposed 
into  a  number  of  closely  related  substances,  known  as  pectinic 
acids,  and  which  are  usually  combined  with  calcium.  The  term 
PECTINASE  is  applied  to  the  enzymes  which  in  the  presence  of 
lime  coagulates  the  juices  containing  the  dissolved  pectinous  sub- 
stances forming  the  so-called  fruit  jellies.  This  reaction  is  con- 
ditioned on  the  presence  of  lime  and  a  certain  equilibrium  being 
established  between  the  enzyme  and  the  concentrations  of  the  acid 
and  calcium  salts.  Pectose  originates  by  reason  of  certain  changes 
in  the  lamellae  of  cell-walls.  While  it  occurs  in  appreciable  quan- 
tities in  those  fruits  that  have  the  properties  of  producing  jelly, 
it  is  probably  very  widely  distributed. 


244  A  TEXT-BOOK  OF  BOTANY. 

CYTASES  (cellulases)  is  the  name  applied  to  those  enzymes 
which  are  capable  of  dissolving  cellulose.  An  enzyme  of  this 
character  is  located  in  the  aleurone  layer  and  in  the  epithelium  of 
the  scutellum  in  the  germinating  grain  of  barley.  It  is  also  found 
in  the  endosperm  of  the  date  palm,  the  cytase  being  formed  in 
the  embryo  and  the  dissolved  products  being  used  up  as  food. 
Enzymes  of  this  character  are  also  found  in  wood-destroying 
fungi  and  bacteria. 

PROTEIN ASES  (carbamases)  is  the  name  applied  to  those 
enzymes  which  break  down  the  true  proteins  or  carbamide  deriva- 
tives. They  are  always  accompanied  in  the  plant  cells  by  other 
ferments,  and  occur  especially  in  seeds,  being  more  abundant  in 
those  containing  oil  than  starch,  as  hemp,  mustard,  castor  oil, 
and  flaxseed.  They  are  also  found  in  certain  fleshy  fruits,  as 
figs  and  pineapple;  succulent  leaves,  as  Agave,  and  in  insectivo- 
rous plants.  In  the  fruit  and  other  parts  of  the  papaw  tree  ( Carica 
Papaya}  occurs  a  proteolytic  enzyme,  called  Papain,  which  readily 
digests  fibrin,  thus  behaving  like  trypsin,  a  ferment  in  the  pan- 
creatic juice.  A  similar  ferment,  called  Bromelin,  has  been  ex- 
tracted from  the  fleshy  pulp  of  the  pineapple.  Ferments  like 
Papain  and  Bromelin  are  naturally  of  very  great  interest,  as  they 
behave  like  the  animal  ferments,  pepsin  and  trypsin.  The  Papain 
of  commerce  seems  to  be  of  varying  composition,  and  unless  ob- 
tained from  authentic  sources  is  not  reliable. 

CHYMASES  OR  ENZYMES  which  effect  the  clotting  of  milk. 
The  coagulating  action  of  the  fig  (Ficus  Carica}  was  known  to  the 
ancients.  This  action  has  been  shown  by  Chodat  and  Rouge  to 
be  due  to  a  vegetable  chymase  and  called  by  them  "  sykochymase." 
A  large  number  of  plants  possess  the  property  of  rendering  milk 
ropy.  Of  these  the  following  may  be  mentioned :  Ranunculus 
bulbosus,  Capsella  Bursa-pastoris,  Plantago  lanceolata,  Medicago 
lupulina,  Pinguicula  vulgaris,  Artichokes,  etc.  An  enzyme  of  this 
character  has  also  been  found  in  germinating  seeds  of  Ricinus 
communis,  Pisum,  Datura,  etc.,  and  some  of  the  fungi. 

ZYMASE,  an  enzyme  causing  the  decomposition  of  glucose  with 
the  formation  of  alcohol  and  carbon  dioxide.  This  decomposition, 
known  as  alcoholic  fermentation,  is  considerably  less  simple  than 
was  formerly  supposed,  a  number  of  enzymes  and  subsidiary  sub- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       245 

stances  taking  part  in  the  reaction.  Zymases  are  widely  dis- 
tributed throughout  the  entire  plant  kingdom,  and  occur  in 
greatest  amounts  in  yeasts  and  other  organisms  which  induce 
alcoholic  fermentation.  The  enzyme,  which  causes  the  transfor- 
mation of  glucose  into  lactic  acid  and  is  secreted  by  lactic  acid 
bacteria,  has  been  given  the  name  of  "  lactic  acid  bacteria-zymase." 

OXYDASES  is  the  name  applied  to  those  enzymes  in  which  the 
decomposition  or  reaction  involves  an  oxidation.  Several  kinds 
of  oxydases  are  recognized,  depending  upon  the  nature  of 
the  original  substance  that  is  broken  down.  ( i )  Alcoholase,  the 
enzyme  of  acetic  bacteria  which  oxidize  ethyl  alcohol  to  acetic 
acid.  (2)  Phenolases  include  the  laccases,  the  oxidizing  enzymes 
found  in  the  lac-tree  (Rhus  succedanea),  and  in  some  other 
plants.  The  black  lacquer  covering  the  beautiful  Japanese  vases 
and  boxes,  and  which  is  the  most  indestructible  varnish  known  to 
man,  is  formed  by  an  oxidizing  enzyme  acting  on  the  phenolic 
resins  of  the  lac-tree. 

Catalases  in  their  chemical  action  resemble  some  of  the  col- 
loidal metals,  in  that  they  are  able  to  decompose  hydrogen 
peroxide  with  the  liberation  of  oxygen.  Enzymes  of  this  char- 
acter have  been  found  in  virtually  all  plant  juices.  Catalases  are 
of  two  kinds,  one  soluble  in  water,  occurring  in  the  seeds  of  apple 
and  peach,  and  an  insoluble  form  found  in  the  leaves  of  clover, 
rose,  and  spruce.  Highly  active  catalases  are  also  obtained  from 
fungi,  yeasts,  and  bacteria. 

While  some  of  the  vegetable  ferments  have  been  isolated  and 
are  prepared  on  a  commercial  scale,  as  diastase  and  the  peptic 
enzyme  papain  found  in  the  latex  of  Carica  Papaya,  in  other 
cases  the  ferment-producing  organisms  themselves  are  used  in 
a  number  of  industries  involving  fermentation  processes,  as  the 
yeast-plants  and  certain  of  the  molds  and  bacteria. 

The  microchemical  study  of  the  ferments  is  attended  with  cer- 
tain difficulty  on  account  of  the  lack  of  specific  reagents  for  their 
detection.  The  most  that  can  be  done  is  to  study  the  products 
formed  by  their  action  upon  certain  other  constituents  of  the  cell. 
(Consult  "  General  Chemistry  of  the  Enzymes,"  by  Hans  Euler, 
translation  by  Thomas  H.  Pope.) 


246 


A  TEXT-BOOK  OF  BOTANY. 
EXAMINATION  OF  CELL-CONTENTS 


PROTOPLASMIC 

NON-PROTOPLASMIC 

Crystalline 

Crystalloidal 

Amorphous 

i.  Cytoplasm 
2.   Nucleus 
3.  Plastids 

4.  Calcium  oxalate 
5.  Sugars 
6.  Alkaloids 
7.   Glucosides 
8.  Phyto-globulins 

9.  Starch 
10.  Inulin 

ii.   Mucilage 
12.  Tannin 
13.  Resin 
14.  Oil 
15.  Latex 
1  6.   Calcium  carbonate 

i,  2,  and  3  have  characteristic  appearance  (see  Frontispiece). 
4.  Crystals  of  characteristic  forms,  soluble  in  hydrochloric  acid 
and  insoluble  in  acetic  acid.  5.  Crystalline  in  fresh  material 
treated  with  alcohol.  The  glucoses  give  a  reddish  precipitate  with 
Fehling's  solution.  6.  Piperine  separates  in  definite  crystals  in 
the  plant  cell ;  the  alkaloids  of  hydrastis  form  crystallizable  salts 
with  sulphuric  or  nitric  acids ;  the  alkaloids  in  hydrastis,  ipecac, 
coffee,  tea,  and  guarana  yield  crystalline  sublimates.  7.  Concen- 
trated sulphuric  acid  gives  with  strophanthin  a  bright  green  color. 
8.  Phyto-globulins  form  definite  crystals  (see  paragraph  on 
aleurone  grains).  9.  Blue  with  dilute  iodine  solution,  except  the 
amylo-dextrin  starches,  as  mace,  which  are  colored  red.  10. 
Sphero-crystals  in  fresh  material  treated  with  alcohol,  n.  Colored 
blue  with  alcoholic  solutions  of  methylene  blue.  12.  Reddish- 
brown  with  copper  acetate  solutions.  13.  Terpene  resins  are 
colored  green  with  copper  acetate  solutions.  14.  Separation  in 
the  form  of  large  globules  on  the  application  of  sulphuric  acid  or 
solution  of  hydrated  chloral.  The  volatile  oils  are  more  soluble  in 
alcohol  than  fixed  oils,  the  latter  being  completely  removed  from 
the  cells  by  the  use  of  ether  or  other  similar  solvent.  15.  Latex 
occurs  as  an  emulsion  consisting  of  numerous  globules.  16. 
Calcium  carbonate  dissolves  with  an  effervescence  on  the  addi- 
tion of  hydrochloric  acid  or  acetic  acid. 

Factors  Influencing  Growth. — Plants  have  certain  inherent 
or  inherited  tendencies  or  characters  which  make  up  the  inner 
constitution,  arid  this  cannot  be  modified  by  external  agencies 
except  within  more  or  less  narrow  limits.  Depending  upon  this 
character  we  find  plants  as  different  in  kind  as  the  apple  tree 
and  pine  growing  under  precisely  the  same  conditions.  In  other 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       247 

words,  the  character  of  the  structure  is  determined  in  the  main 
by  the  nature  of  the  organism.  It  is  true  that  an  apple  tree  may 
grow  better  in  one  locality  than  another,  but  it  is  still  an  apple 
tree  whether  it  be  dwarfed  or  attain  to  the  full  measure  of  its 
growth.  These  slight  changes  in  the  character  are  known  as 
accidental  variations.  Frequently  they  are  the  result  of  tempo- 
rary conditions  and  are  not  repeated  in  the  succeeding  genera- 
tion. On  the  other  hand,  if  the  special  conditions  remain  these 
individual  variations  may  be  repeated  in  generation  after  gen- 
eration and  finally  become  permanent  characters. 

The  gradual  change  in  the  structure  and  nature  of  organisms 
which  takes  place  through  long  periods  of  time  is  spoken  of  as 
EVOLUTION.  In  some  cases  specific  changes  in  the  characters  of 
plants  arise  rather  suddenly  without  any  known  cause,  and  such 
changes  are  spoken  of  as  saltations  or  MUTATIONS. 

The  factors  essential  for  growth  in  all  cases  are  food,  water, 
and  a  certain  temperature.  Among  the  food  elements  we  may 
mention  as  of  chief  importance,  carbon,  hydrogen,  oxygen,  and 
nitrogen.  Some  of  the  other  elements  are  also  essential  to  most 
plants,  although  they  occur  in  relatively  small  proportion  in  the 
plant,  as  potassium,  magnesium,  phosphorus,  sulphur,  iron,  and 
calcium.  The  latter  element  does  not  seem  to  be  necessary  to 
the  normal  development  of  some  of  the  Fungi  and  certain  Algse. 

Water  permeates  all  parts  of  the  plant,  and  when  the  cells 
are  in  the  normal  turgescent  state  it  contains  more  than  half 
its  weight  of  water.  When  the  supply  of  water  falls  below  the 
normal  the  plants  begin  to  droop  and  finally  die.  The  need  of 
plants  varies  greatly  in  this  particular ;  some  are  aquatic  in  their 
habits  and  live  wholly  in  the  water;  others  can  live  only  on  the 
land ;  and  still  others  are  adapted  to  desert  regions. 

The  degree  of  temperature  necessary  for  growth  varies  within 
certain  limits  for  each  kind  of  plant,  but,  as  is  stated  by  Pfeffer, 
the  greatest  extremes  are  shown  by  Fungi,  Bacteria,  and  the 
lower  Algse.  Generally  speaking,  the  most  favorable  temperature 
for  growth  is  between  24°  and  34°  C. 

Besides  the  factors  enumerated  there  are  other  factors  which 
influence  growth.  They  include  light,  gravity,  mechanical 
agencies,  etc.,  and  are  sometimes  spoken  of  as  external  stimuli. 


248  A  TEXT-BOOK  OF  BOTANY. 

It  is  difficult  to  separate  those  factors  which  act  solely  as 
external  stimuli  from  those  which  are  essential  to  the  normal 
growth  of  the  plant  and  which  may  be  considered  as  physiological 
factors.  For  example,  light  under  certain  conditions  may  be 
regarded  as  in  the  nature  of  an  external  stimulus  and  not  essen- 
tial to  the  growth  of  the  plant,  while  in  other  cases  it  has  a  direct 
influence  on  normal  growth  and  is  essential  to  the  life  of  the 
plant,  as  in  all  plants  or  parts  of  plants  where  photosynthesis 
takes  place. 

In  addition  to  the  essential  food  elements,  there  are  many 
substances  which  affect  the  growth  of  plants  which  may  be 
grouped  as  chemical  stimuli,  such  as  (a)  the  substances  secreted 
by  gall-forming  insects,  (b)  in  a  certain  measure  some  of  the 
substances  produced  by  Fungi,  (c)  and  numerous  substances  not 
found  as  normal  constituents  of  the  plant.  Depending  upon  the 
amount  of  the  substance  present  and  the  conditions  under  which 
it  is  supplied,  the  substance  may  act  as  a  poison  and  injure  the 
plant,  or  it  may  accelerate  growth,  or  cause  abnormal  develop- 
ment. 

This  subject  has  an  important  bearing  on  the  physiological 
testing  of  drugs.  Robert  states  that  in  determining  the  qualities 
of  a  new  chemical,  preliminary  experiments  should  be  conducted 
on  lower  plants  and  animals  before  trying  it  on  man.  Of  the 
plants  which  have  been  used  in  the  testing  of  poisons  the  follow- 
ing may  be  mentioned :  Oscillaria,  Spirulina,  Nostoc,  Zygnema, 
Spirogyra,  Saccharomyces,  Mucor,  Elodea,  Lemna,  Pistia, 
Potamogeton,  Myriophyllum,  Ceratophyllum,  Tradescantia,  seed- 
lings of  grasses,  lupine,  bean,  pea,  corn,  etc.  Kraemer  has  em- 
ployed seedlings  of  Lupinus  albus  and  Pisum  sativum  in  testing 
solutions  containing  ethyl  alcohol,  strychnine  nitrate,  brucine 
sulphate,  and  tincture  of  nux  vomica  (Amer.  Jour.  Pharm., 
1900,  p.  472). 

FOOD  OF  PLANTS. — It  has  already  been  pointed  out  that  certain 
of  the  chemical  elements  are  necessary  for  the  growth  of  plants, 
and  that  these  are  derived  partly  from  the  surrounding  atmos- 
phere and  partly  from  the  soil.  Those  elements  derived  from 
the  air  are  either  themselves  gases  or  exist  in  combination  in  the 
form  of  gas,  and  include  oxygen,  nitrogen  in  exceptional  cases, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       249 

and  carbon  dioxide,  the  source  of  the  carbon  entering  into  the 
carbon  compounds  formed  by  plants. 

The  elements  obtained  by  plants  from  the  soil  exist  in  com- 
bination with  other  elements  and  must  be  in  the  form  of  solution 
to  be  absorbed.  The  soil  consists  largely  of  mineral  substances, 
together  with  certain  organic  products  (humus).  The  water  held 
in  the  soil  not  only  acts  as  a  medium  for  carrying  the  soluble 
constituents  in  the  soil  to  the  plant,  but  is  itself  an  important  food 
product,  being  the  source  of  the  hydrogen  used  by  plants,  as  also 
of  assimilable  oxygen.  Among  the  mineral  constituents  of  the 
soil  that  are  useful  to  plants  are  ammonium  salts  and  nitrates, 
sulphates,  phosphates,  chlorides,  silicates,  and  carbonates.  When 
plants  are  collected  and  subjected  to  a  temperature  of  about  110° 
C.  the  water  is  driven  off,  and  then  if  heat  sufficient  to  incinerate 
the  material  is  applied  the  organic  matter  is  driven  off  in  the 
form  of  gases,  leaving  the  mineral  constituents  in  the  form  of 
ash,  as  calcium,  magnesium,  iron,  potassium,  sodium,  and  a  few 
other  elements. 

FORMATION  OF  LEAFMOLD. — When  the  leaves  of  a  tree  fall  to 
the  ground  they  begin  to  decay  and  ultimately  they  are  dis- 
integrated, and  their  substances  become  incorporated  with  the 
other  elements  of  the  soil.  The  same  thing  happens  with  the 
leaves,  stems,  and  roots  of  herbaceous  plants.  Such  organic 
matter  is  one  of  the  chief  sources  of  food  for  plants,  and  its 
presence  in  the  soil  is  therefore  of  fundamental  importance  in  the 
maintenance  of  the  vegetable  mantle  of  the  earth.  Coville  (Jour. 
Wash.  Acad.  Sci.,  1913,  p.  79)  determined  the  rate  in  decomposi- 
tion of  leaves  and  used  silver  maple,  sugar  maple,  red  oak,  and 
Virginia  pine.  These  were  exposed  to  the  weather  in  barrels 
and  in  concrete  pits.  In  one  experiment  a  mass  of  trodden  silver 
maple  leaves  two  feet  in  depth,  with  an  initial  acidity  of  0.92 
normal,  was  reduced  in  a  single  year  to  a  three-inch  layer  of 
black  mold  containing  only  a  few  fragments  of  leaf  skeletons 
and  giving  an  alkaline  reaction.  Sugar  maple  leaves  have  shown 
a  slower  rate  of  decomposition  than  those  of  silver  maple,  while 
red  oak  leaves  still  showed  an  acidity  of  o.oio  normal  after  three 
years'  exposure,  and  leaves  of  Virginia  pine  an  acidity  of  0.055 
normal  under  the  same  conditions.  During  the  decomposition  of 


250  A  TEXT-BOOK  OF  BOTANY. 

leaves  the  acid  substances  are  decomposed  and  to  some  extent 
dissipated  in  the  form  of  gases. 

The  chief  agents  in  the  decay  of  leaves  are  fungi  and  bacteria. 
A  number  of  forms  of  animal  life  also  contribute  greatly  to  the 
decay  also,  as  earthworms,  larvae,  flies  and  beetles  and  myriapods 
or  thousand-legged  worms.  Coville  distinguishes  two  kinds  of 
leaf  mold :  (a)  In  which  the  leaves  show  a  condition  of  imperfect 
decomposition,  due  to  the  development  and  maintenance  of  an 
acid  condition,  which  is  inimical  to  the  growth  of  microorganisms 
of  decay.  Because  of  the  resemblance  of  this  mat  or  turf  to  bog 
peat  in  appearance,  structure,  and  chemical  composition,  and  be- 
cause it  supports  a  type  of  vegetation  similar  to  that  of  bog  peat, 
it  has  been  named  UPLAND  PEAT.  This  is  characteristic  of  the 
sandy  pine  and  oak  woods,  where  grow  huckleberries,  laurel, 
princess  bine,  pink  lady's  slipper,  trailing  arbutus,  etc.  (b)  The 
other  is  characteristic  of  the  black  mellow  mold  made  up  of  com- 
pletely rotted  leaves,  the  acidity  being  neutralized  in  part  by  the 
calcium  present  in  the  leaves  and  partly  by  the  underlying  soil, 
which  is  usually  of  a  calcareous  nature.  This  is  characteristic  of 
forests  of  tulip  poplar,  ash,  and  oaks,  in  which  grow  sanguinaria, 
caulophyllum,  hydrastis,  trillium,  etc. 

ORGANIC  CONSTITUENTS  IN  SOIL. — During  the  past  few  years 
Schreiner  and  his  associates  in  the  Bureau  of  Soils,  U.  S.  Depart- 
ment of  Agriculture,  have  isolated  and  identified  a  number  of 
soil  constituents.  They  have  found  that  certain  of  these  con- 
stituents, as  dihydroxystearic  acid,  are  rather  characteristic  of 
poor  soils,  and  that  the  effect  of  fertilizers  on  such  soils  was  to 
increase  their  fertility  by  neutralizing  their  toxic  constituents 
rather  than  by  the  addition  of  any  food  constituents  to  the  soil. 
The  compounds  isolated  by  them  have  varied  considerably,  and 
may  be  grouped  into  the  following  classes :  i ,  Paraffin  hydro- 
carbons, represented  by  hentriacontane ;  2,  hydroxy- fatty  acids, 
represented  by  a-monohydroxystearic  acid  and  dihydroxy- 
stearic acid ;  3,  organic  acids  of  unknown  constitution,  represented 
by  agroceric  acid,  paraffinic  acid,  lignoceric  acid,  and  a  number  of 
resin  acids ;  4,  esters  and  alcohols,  represented  by  agrosterol,  phy- 
tosterol,  glycerides  of  fatty  acids,  and  resin  esters ;  5,  carbohy- 
drates, represented  by  pentosans  and  pentose  sugars ;  6,  hexone 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       251 

bases,  represented  by  histidine  and  arginine  ;  7,  pyrimidine  deriva- 
tives, represented  by  cytosine ;  8,  purine  bases,  represented  by 
xanthine  and  hypoxanthine ;  9,  pyridine  derivatives,  represented 
by  picoline  carboxylic  acid. 

ROOT  ABSORPTION. — Notwithstanding  the  various  agents 
which  are  at  work  tending  to  break  down  and  dissolve  the  sub- 
stances contained  in  the  soil,  as  soil  bacteria,  the  liquids  given  to 
the  soil  by  the  roots  of  the  plants  themselves,  the  presence  of  the 
so-called  humic  acids,  and  the  action  of  water  and  air,  it  has  been 
shown  that  the  soil  water  is  an  exceedingly  weak  solution.  This 
is  largely  due  to  the  peculiar  absorptive  and  fixing  power  of  the 
soil  itself. 

The  dilution  of  the  aqueous  solution  of  the  soil  constituents 
is  a  matter  of  very  great  significance,  for  upon  this  depends  its 
absorption  by  the  root  hairs.  While  other  parts  of  roots  have  cer- 
tain absorptive  powers,  the  root  hairs  have  been  defined  as  the 
organs  of  absorption  of  the  plant.  They  are  very  delicate  in 
structure  and  contain  protoplasm.  Their  absorbent  function  de- 
pends upon  the  principle  that  when  a  membrane  (animal  or 
vegetable)  is  interposed  between  two  liquids  of  unequal  density, 
the  less  dense  liquid  will  pass  through  the  membrane  and  mix 
with  the  denser  liquid.  This  process  is  known  as  OSMOSIS,  and 
when  a  liquid  passes  outward  through  a  membrane  or  cell-wall 
it  is  called  exosmosis,  and  when  inward  it  is  called  endosmosis. 
The  soil  is  made  up  of  minute  earth  particles,  each  of  which  is 
surrounded  by  a  thin  film  or  envelope  of  water,  and  it  is  this  por- 
tion of  the  soil  liquid  that  is  absorbed  by  the  root  hairs.  The  root 
hairs  come  into  close  contact  with  these  soil  particles ;  in  fact, 
appear  to  grow  fast  to  them,  and  the  cell-liquid  in  the  root  hairs 
being  denser  than  that  surrounding  the  soil  particles,  the  latter 
passes  through  the  wall  into  the  root  hairs. 

If,  on  the  other  hand,  the  water  supplied  to  the  roots  of  plants 
should  contain  an  excess  of  soluble  material,  the  plant  will  be 
injured.  In  this  case  exosmosis  ensues  and  the  plant  loses  some 
of  its  own  liquids  or  cell-sap  and  will  show  signs  of  wilting.  It 
is  well  known  that  if  cultivated  plants  are  supplied  with  strong 
solutions  of  fertilizer  the  plants  will  be  injured  rather  than 
benefited. 


252  A  TEXT-BOOK  OF  BOTANY. 

ROOT  PRESSURE. — The  distribution  of  the  water  absorbed  by 
the  roots  to  other  parts  of  the  plant  is  influenced  by  a  number  of 
factors,  which  are  commonly  spoken  of  together  as  root  pressure. 
Among  these  are  osmosis  within  the  plant,  due  to  unequal  density 
of  the  liquids  in  different  cells;  the  changes  in  the  equilibrium  of 
the  cell-liquids,  due  to  chemical  changes;  and  the  transpiration 
of  water  from  the  leaves,  thus  establishing  a  flow  of  liquids  from 
the  roots  upward,  which  is  usually  spoken  of  as  the  ASCENT  OF 
SAP.  The  cell-sap  passes  upward  through  the  xylem  for  the  most 
part,  carrying  constituents  obtained  from  the  soil  to  the  growing 
parts,  where  they  are  combined  with  the  products  of  photosyn- 
thesis, and  through  a  series  of  reactions  protoplasm  is  finally 
built  up. 

OXIDATION. — The  free  oxygen  taken  in  by  plants  through  the 
stomata  and  lenticels  serves  the  same  purpose  in  plants  as  that 
inhaled  by  animals,  namely,  the  oxidation  of  certain  compounds, 
whereby  part  of  the  energy  necessary  for  vital  activity  is  lib- 
erated. Oxygen  is  required  by  all  parts  of  the  plant.  When  the 
roots  of  plants,  such  as  those  of  Zea  Mays,  are  surrounded  by 
water  so  as  to  exclude  the  air  the  plants  will  become  yellow. 
Germinating  seeds  consume  a  large  amount  of  oxygen,  but  not 
all  the  energy  formed  is  used  by  the  plantlet,  much  of  it  escaping 
as  heat,  as  in  the  germination  of  barley  in  the  preparation  of  malt. 
Those  plants  dependent  upon  the  presence  of  free  atmospheric 
oxygen  are  called  AEROBES,  while  those  which  are  not  thus  de- 
pendent, as  certain  fungi  and  bacteria,  are  called  ANAEROBES. 

METABOLISM. — Processes  of  construction  and  destruction  are 
going  on  simultaneously  in  the  plant,  and  these  are  all  grouped 
under  the  general  name  of  metabolism.  The  processes  whereby 
complex  substances  are  built  up  from  simpler  ones,  as  in  photo- 
synthesis, are  together  spoken  of  as  CONSTRUCTIVE  METABOLISM 
(anabolism),  while  those  which  involve  the  breaking  down  of 
complex  compounds  into  simpler  ones,  either  through  oxidation 
or  other  chemical  action,  as  when  sugar  is  changed  into  carbon 
dioxide  and  water,  are  grouped  under  the  head  of  DESTRUCTIVE 
METABOLISM  (catabolism) . 

Inasmuch  as  the  carbon  dioxide  of  the  atmosphere  and  the 
water  taken  up  by  the  roots  together  with  the  mineral  salts  which 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       253 

it  holds  in  solution  are  the  only  sources  of  the  food  supply  of 
green  plants,  it  follows  that  the  highly  complex  proteins  trace 
their  origin  to  these  comparatively  simple  substances.  By  some 
it  is  supposed  that  the  final  stages  in  the  building  up  or  synthesis 
of  the  proteins  take  place  in  the  leaves,  but  it  is  probable  that  they 
take  place  in  all  the  growing  parts  of  the  plant.  It  has  already 
been  stated  in  the  paragraph  on  proteins  that  seeds  contain  re- 
serve materials  which  are  broken  up  into  simpler  compounds 
through  the  action  of  certain  enzymes,  and  thus  made  available 
for  the  seedling.  It  is  claimed  that  these  compounds  are  prin- 
cipally amino  acids,  and  that  of  these  aspartic  and  glutaminic  acids 
occur  in  largest  amount  and  that  these  two  acids  are  found  in 
different  relative  amounts  in  different  plants.  It  is  furthermore 
claimed  by  some  authors  that  by  certain  syntheses  these  com- 
pounds are  respectively  converted  into  asparagin  and  glutamin, 
both  of  which  occur  as  reserve  materials  in  seeds  and  in  other 
parts  of  plants  as  well.  Yet  other  syntheses  take  place  whereby 
asparagin  and  similar  bodies  are  converted  into  albumin  and  other 
proteins.  In  the  Coniferse  the  part  played  by  asparagin  and 
glutamin  in  protein  syntheses  is  taken  by  arginin,  which  substance 
is  found  in  considerable  amount  in  the  seeds  of  the  plants  of  this 
group. 

GROWING  POINTS  AND  MERISTEMS. — Plants  are  distinguished, 
for  the  most  part,  by  having  distinct  growing  points,  known  as 
vegetative  points.  These  occur  at  the  apex  of  shoots  and  roots  and 
at  definite  lateral  points,  being  in  the  stem  near  the  surface  and 
in  roots  beneath  the  endodermis.  The  walls  of  the  cells  in  these 
regions  are  very  thin  and  consist  almost  entirely  of  cellulose. 
The  cells  are  compactly  arranged  and  are  more  or  less  polygonal 
Or  somewhat  elongated.  They  are  rich  in  protoplasm,  capable  of 
rapid  division,  and  constitute  the  tissue  known  as  PRIMARY  MERI- 
STEM.  In  the  root  three  kinds  of  primary  meristem  (Fig.  132) 
are  distinguished:  (i)  The  PLEROME  (m,  f,  g),  an  axial  meri- 
stem, which  gives  rise  to  the  central  cylinder  or  stele;  (2)  the 
PERIBLEM  (x,  r),  or  meristematic  tissue,  which  gives  rise  to  the 
primary  cortex;  and  (3)  the  DERMATOGEN  (e),  from  which  the 
epidermis  is  developed.  In  addition  to  these  three  meristematic 
zones  there  is  at  the  apex,  lying  next  to  the  dermatogen,  a  meri- 


254  A  TEXT-BOOK  OF  BOTANY. 

stematic  group  of  cells  which  give  rise  to  the  root-cap,  known  as 

the  CALYTROGEN    (s). 

At  the  growing  point  of  the  stem  three  meristematic  zones  are 
also  distinguished,  namely,  plerome,  periblem,  and  dermatogen. 
They  are  not,  however,  so  well  marked  as  in  the  case  of  roots. 

The  tissues  which  are  developed  from  the  primary  meristems 
constitute  the  PRIMARY  STRUCTURE.  With  the  growth  in  thickness 
of  the  stems  and  roots  of  Dicotyledons  other  meristematic  cells, 
known  as  SECONDARY  MERISTEMS,  arise.  These  are  of  two  kinds : 
( i )  One  which  gives  rise  to  the  xylem  and  phloem,  known  as  the 
CAMBIUM,  and  (2)  another  which  gives  rise  to  the  cork,  known  as 
PHELLOGEN.  The  tissues  formed  from  the  secondary  meristems 
constitute  the  SECONDARY  STRUCTURE  of  older  dicotyledonous 
stems  and  roots. 

While  the  point  of  vegetation  in  the  higher  plants  (spermo- 
phytes)  embraces  a  number  of  cells,  in  the  lower  plants  the  tissues 
can  be  traced  back  to  a  single  APICAL  CELL. 

CELL- WALL. — Origin  and  Composition.— It  is  formed  by  the 
protoplasm,  and  varies  in  composition  at  different  stages  of  the 
growth  of  the  cell,  and  according  to  the  various  functions  it  has 
to  perform. 

In  order  to  thoroughly  understand  the  nature  and  composi- 
tion of  the  cell-wall,  it  is  necessary  to  study  the  origin  and  forma- 
tion of  new  cells.  Growth  of  the  plant  is  attended  not  only  by 
an  increase  in  the  size  of  the  cells,  but  by  their  division  (Fig.  85) 
new  cells  are  also  formed.  Cells  that  have  the  property  to  divide 
and  form  new  cells  are  known  as  meristematic  cells  and  constitute 
the  MERISTEM.  The  new  and  dividing  walls  resulting  from  the 
division  of  the  cells  consist  of  a  number  of  substances.  When  a 
cell  divides,  the  two  daughter  protoplasts  which  result  from  the 
division  of  the  nucleus  and  cytoplasm  are  separated  by  the  forma- 
tion of  a  new  wall  between  them  (Fig.  85).  The  first  layer 
formed  is  apparently  different  from  the  subsequent  layers  and  is 
known  as  the  middle  plate  or  MIDDLE  LAMELLA.  This  layer  is 
soluble  in,  or  readily  attacked  by,  solutions  of  the  alkalies  or  solu- 
tions containing  free  chlorine.  It  is  insoluble  in  sulphuric  acid, 
and  readily  stained  by  the  aniline  dyes.  .  While  usually  more  or 
less  permanent,  this  middle  plate  may  be  finally  absorbed,  as  in 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       255 

the  glandular  hairs  of  kamala,  or  it  may  be  changed  into  mucilage, 
as  in  chondrus,  or  transformed  into  pectin  compounds,  as  in  fleshy 
roots  and  fruits. 

To  this  middle  plate  is  added  on  either  side  by  the  newly 
formed  protoplasts  a  layer  of  substance  closely  resembling  cellu- 
lose, this  constituting  the  PRIMARY  MEMBRANE  or  primary  lamella. 

As  the  cells  become  older  the  wall  increases  in  thickness 
through  the  addition  of  other  layers,  much  in  the  same  manner  as 
the  starch  grain  increases  in  size.  These  subsequent  layers  are 
known  as  SECONDARY  LAMELLA.  In  a  few  cells  the  secondary 
lamellae  may  consist  of  pure  cellulose.  As  a  rule,  however,  the 
wall  is  rather  complex  and  consists  of  alternate  layers  of  cellulose 
with  other  substances.  Some  of  these,  as  mucilage,  may  be  a 
simple  modification  of  cellulose,  others  may  consist  of  cellulose 
in  combination  with  other  substances,  as  in  the  ligno-cellulose  walls 
of  stone  cells,  or  the  walls  may  consist  of  cellulose  and  suberin  as 
in  cork  cells,  or  of  cutin-cellulose  as  in  epidermal  cells.  Again, 
there  may  be,  through  the  action  of  special  enzymes,  a  decomposi- 
tion of  the  cellulose,  resulting  in  the  formation  of  oils,  resin,  and 
wax.  Furthermore,  it  would  not  seem  improbable  that  some  of 
the  secondary  substances  in  the  wall  are  direct  products  of  the 
protoplasm  and  secreted  in  the  cell-wall,  as  silica  and  calcium 
oxalate  in  epidermal  cells.  The  substance  called  pectin  originates 
as  a  modification  of  the  intercellular  substance,  and  is  peculiar 
to  some  fruits. 

As  showing,  to  some  extent,  the  complexity  of  the  lamellae 
in  the  cell-wall,  the  following  modifications  of  the  wall  in  secretion 
cells  may  be  given:  i.  The  entire  outer  cell- wall  may  consist  of 
a  thin  layer  of  suberized  lamellae,  beneath  which  is  a  secondary 
mucilaginous  layer  that  develps  the  secretion,  e.g.,  Hedychium 
Gardnerianum.  2.  The  outer  lamellae  of  the  cell-wall  may  con- 
sist of  suberin;  beneath  this  is  a  cellulose  lamellae,  which  only 
after  treatment  with  a  solution  of  potassium  hydroxide  is  colored 
blue  with  chlor-zinc  iodide;  this  is  followed  by  a  mucilaginous 
layer,  e.g.,  Laurus  nobilis,  Curcuma  Zedoaria,  Cinnamomum  Cas- 
sia, Zingiber  officinale,  Acorus  Calamus.  3.  The  outer  layer  may 
consist  of  cork,  beneath  which  is  a  cellulose  layer  that  is  colored 
blue  upon  treatment  with  chlor-zinc  iodide  without  the  previous 


256  A  TEXT-BOOK  OF  BOTANY. 

use  of  potassium  hydroxide ;  to  this  is  then  added  a  mucilagino-us 
layer,  as  in  the  secretion  cells  of  Valeriana  officinalis  and  Magnolia 
grandiflora.  4.  The  outer  layer  may  be  suberized,  but  the  cellulose 
layer  beneath  this  is  not  colored  blue  until  the  walls  have  been 
first  treated  with  Schultze's  solution ;  this  then  is  followed  by  a 
mucilaginous  layer,  e.g.,  Piper  nigrum,  Piper  Cubeba,  and  Sassa- 
fras  officinale.  5.  The  outer  and  inner  layers  may  be  suberized, 
and  between  these  are  fine  lamellae  of  cellulose,  e.g.,  Croton 
Eluteria.  6.  The  outer  layer  may  be  suberized,  beneath  which  is 
a  layer  of  lignocellulose,  followed  by  a  mucilaginous  layer,  e.g., 
Caly can-thus  floridus.  7.  The  outer  layer  may  be  colored  yellow 
with  chlor-zinc  iodide  and  dissolves  in  sulphuric  acid,  while  the 
inner  layer  is  suberized,  e.g.,  fruit  of  Conium  maculatum. 

CELLULOSE  in  its  various  modifications  constitutes  the  greater 
proportion  of  the  cell-wall.  The  cellulose  making  up  the  cotton 
fiber  may  be  said  to  be  the  typical  cellulose,  and  is  known  as 
"  cotton  cellulose."  It  is  soluble  in  copper  ammonium  sulphate 
solution ;  is  colored  blue  with  chlor-zinc-iodide  solution  or  iodine 
and  sulphuric  acid,  and  is  stained  by  acid  phenolic  dyes,  as  alizarin, 
if  previously  treated  with  basic  mordants,  as  basic  salts  of 
aluminum,  etc. 

The  following  solutions  are  used  in  the  testing  of  mixed 
fabrics  containing  cotton  :  •  i.  A  solution  of  I  part  of  zinc  chloride 
in  2  parts  of  hydrochloric  acid  will  dissolve  cellulose  in  about 
one-half  minute.  2.  Upon  heating  a  piece  of  fabric  in  a  saturated 
solution  of  aluminum  chloride,  the  cotton  becomes  friable,  the 
wool  remaining  unaffected. 

According  to  their  origin  in  the  plant,  or  their  behavior  toward 
reagents,  the  cellulose  walls  may  be  divided  into  the  following 
groups:  (i)  Lignocellulose  walls;  (2)  protective  cellulose  walls; 
(3)  reserve  cellulose  walls;  (4)  mucilage  cellulose  walls,  and  (5) 
mineral  cellulose  walls. 

Lignocellulose  walls  are  composed  of  true  cellulose  and  a 
non-cellulose  (the 'so-called  lignin  or  lignone),  these  constituting 
the  woody  (so-called  lignified)  portion  of  plants  and,  in  some 
instances,  also  the  bast  portion  of  the  bark.  The  lignocelluloses 
are  colored  yellow  with  chlor-zinc  iodide,  or  iodine  and  sulphuric 
acid.  On  account  of  their  containing  in  some  instances  furfurol, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.     257 

coniferin,  vanillin,  cinnamic  aldehyde,  benzaldehyde  or  other  alde- 
hydic  substances,  they  give  definite  color-reactions  with  certain 
reagents.  They  are  also  stained  by  the  aniline  dyes,  as  fuchsin, 
saf  ranin,  gentian  violet,  aniline  blue,  methylene  blue,  etc. 

Aniline  hydrochloride  with  hydrochloric  acid  and  aniline  sul- 
phate with  sulphuric  acid  produce  a  golden-yellow  color  in  cell- 
walls  containing  lignocelluloses. 

A  2  per  cent,  phloroglucin  solution,  used  in  conjunction  with 
hydrochloric  acid,  gives  a  reddish-violet  color  with  the  lignocellu- 
loses, although  there  are  some  celluloses  of  this  class  which  do  not 
respond  to  this  test,  as  flax  (the  bast  fibers  of  Linum).  In  other 
plants  phloroglucin  may  occur  as  a  constituent  of  the  cells. 

Hartwich  and  Winckel  (Arch.  d.  Pharin.,  1904,  p.  462)  have 
shown  that  the  red  coloration  formed  upon  the  addition  of  vanillin 
and  hydrochloric  acid  to  phloroglucin  is  also  produced  by  a  number 
of  other  substances,  viz.,  thymol,  guaiacol,  resorcin,  cresorcin, 
orcin,  pyrogallol,  pyrogallol  dimethyl-ether,  phloroglucin,  oxy- 
hydroquinone,  eugenol,  and  safrol,  but  not  with  phenol,  pyro- 
catechin,  hydroquinone,  or  pyrogallol  trimethyl-ether.  The  re- 
action cannot,  therefore,  be  longer  designated  as  a  phloroglucin 
reaction,  but,  in  a  limited  sense,  as  a  phenol  reaction.  The  same 
color  reaction  is  produced  by  a  number  of  other  substances  which 
contain  a  phloroglucin  molecule,  e.g.,  phloridzin,  maclurin,  luteolin, 
morin,  catechin,  filizin,  gentisin,  and  all  the  phloroglycotannoides, 
as  in  oak  bark  and  cinchona  bark. 

Protective  cellulose  walls  are  composed  of  mixtures  of  lig- 
nocellulose  and  oils  and  waxes,  and  frequently  contain  in  addi- 
tion tannin,  vanillin,  and  other  compounds.  In  the  cuticle  or  epi- 
dermis of  leaves  and  green  stems  the  cellulose  is  associated  with 
a  fatty  compound  known  as  cutin  (or  cutose),  while  in  the  cork 
of  stems  and  roots  it  is  combined  with  suberin  (or  suberose). 
This  class  of  celluloses  is  distinguished  from  cotton  cellulose  and 
lignocellulose  by  being  insoluble  in  sulphuric  acid. 

Reserve  cellulose  walls  are  those  found  in  various  seeds,  as 
in  coffee,  date,  nux  vomica,  etc.  They  behave  toward  reagents 
much  like  the  true  celluloses  (Fig.  135). 

Mucilage  cellulose  walls  consist  of  cellulose  and  mucilage, 
and  are  found  in  all  parts  of  the  plant,  and  in  the  case  of  seeds 
17 


'258  A  TEXT-BOOK  OF  BOTANY. 

are  associated  with  the  protective  celluloses.  They  dissolve  or 
swell  in  water,  are  colored  blue  (as  in  flaxseed)  or  yellowish  with 
iodine,  and  are  stained  with  alcoholic  or  glycerin  solutions  of 
methylene  blue. 

Mineral  cellulose  walls  are  composed  of  cellulose  and  vari- 
ous inorganic  substances,  as  silica,  calcium  oxalate,  or  calcium 
carbonate.  These  are  more  commonly  found  in  the  cell-wall  of 
the  lower  plants,  as  Algae,  Fungi,  and  Equisetaceae.  Calcium  car- 
bonate and  silica  also  occur  in  the  cystoliths  of  the  various  genera 
of  the  Moracese  and  Acanthaceae  (Fig.  113). 

From  what  has  just  been  said  of  the  chemical  composition  and 
structure  of  the  cell- wall,  it  is  seen  that  it  consists  of  lamellae  or 


FIG.  129.  i,  cross-section  of  a  bast  fiber  of  Begonia  as  seen  by  means  of  the  micro- 
polariscope,  and  showing  stratification  of  the  wall.  2,  polariscopic  view  of  a  sphero-crystal 
of  inulin  in  Helianthus  tuberosus. — After  Dippel. 

layers  of  different  substances,  and  in  no  case  does  it  consist  of 
but  a  single  substance ;  but  for  convenience  we  speak  of  a  wall  as 
consisting  of  cellulose,  lignin,  or  suberin,  meaning  thereby  that 
the  wall  gives  characteristic  reactions  for  these  substances. 

PHYTOMELANE,  an  intercellular,  carbon-like  substance.  It  is 
a  black,  structureless  substance,  found  only  in  the  Compositae, 
being  distributed  around  the  sclerenchymatous  fibers  and  stone 
cells  in  a  number  of  fruits.  It  has  also  been  found  in  the  lignified 
cells  of  roots  and  stems  (Fig.  131),  and  occasionally  is  found  in 
the  parenchyma  cells  of  Inula.  In  the  latter  it  occurs  more  or  less 
crystalline,  sometimes  in  the  form  of  short  needles  or  rods  (Fig. 
132).  According  to  'Hanausek  ("  Untersuchungen  iiber  die 
Kohleahnliche  Masse  der  Kompositen  "),  phytomelane  occurs  in 
a  large  number  of  genera  in  the  Compositae.  It  arises  in  the  middle 
lamellae  and  has  a  high  content  in  carbon,  ranging  from  69.76  per 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       259 


cent,  in  Helianthus  annuus  to  76.47  per  cent,  in  Dahlia  variabilis. 
It  is  unaffected  by  most  reagents  except  hydriodic  acid.  It  may 
readily  be  separated  in  unaltered  masses  upon  treatment  of  the 
tissues  with  Wiesner's  chromic  acid  mixture  or  with  Schultze's 
macerating  solution.  Hanausek  considers  the  phytomelane  layer  to 
be  in  the  nature  of  a  mechanical  protection  to  those  fruits  and  seeds 
in  which  the  epidermal  and  hypodermal  layers  scale  off  with  the 
ripening  of  the  fruit.  (Consult  Kraemer  and  Sollenberger,  Amer. 

I  II 


FIG.  130.  Striation  in  cell-wall:  I,  a  portion  of  bast  fiber  in  Oleander,  showing  left 
spiral  bands  as  seen  from  the  outer  surface  (a)  and  the  same  as  seen  from  the  inner  surface 
(b);  II,  portion  of  the  bast  cell  of  Asclepias  syriaca  as  seen  on  the  under  surface;  III,  a 
view  of  the  bast  fiber  of  Asclepias  syriaca  as  seen  when  looking  through  the  middle  of  the 
cell;  IV,  portion  of  tracheid  of  Pinus  sylvestris,  showing  two  views  of  the  striations  of  the 
wall. — After  Dippel  in  "Das  Mikroskop." 

Jour.  Pharm.,  1911,  p.  315;  Senft,  Pharm.  Post,  1914,  No.  30; 
Hanausek,  Ber.  d.  d.  bot.  Ges.,  1911,  p.  558.) 

LAMELLA. — In  some  cells,  as  in  lignified  cells,  the  lamellae 
are  quite  apparent.  In  other  cases  the  use  of  reagents,  as  chromic 
acid  or  chlor-zinc  iodide,  is  necessary  to  bring  out  this  structure. 
The  layering  which  is  observed  in  transverse  sections  of  the  cell- 
wall  is  spoken  of  as  stratification  of  the  wall  (Fig.  129),  whereas 
the  layering  observed  in  longitudinal  or  tangential  sections  is 
referred  to  as  striation  of  the  wall  (Fig.  130). 


2(5o 


A  TEXT-BOOK  OF  BOTANY. 


Thickening  or  Marking  of  Walls. — In  the  formation  of 
the  wall  each  cell  appears  to  work  in  unison  with  its  neighbors 
for  the  building  up  of  the  plant.  The  thickening  of  the  walls 
of  the  cell  is  primarily  for  the  purpose  of  strengthening  the  walls, 
but  if  the  walls  were  uniformly  thickened,  osmosis,  or  the  trans- 
ferral  of  cell-sap  from  one  cell  to  another,  would  be  hindered. 


FIG.  131 .    Phytomelane,  an  intercellular  carbon-like  substance  occurring  on  the  outer  layers 
of  the  stone  cells  in  Brauneria  pallida  (Echinacea  angustifolia) . 

Thus  we  find  that  the  contiguous  walls  of  the  cells  are  thickened 
at  definite  places  opposite  each  other,  leaving  pores  or  canals 
which  permit  rapid  osmosis.  The  pores  thus  formed  are  known 
as  simple  pores,  and  when  seen  in  surface  view  are  somewhat 
elliptical  or  circular  in  outline,  and  may  be  mistaken  for  some  of 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       261 

the  cell-contents.  These  thickenings  assume  a  number  of  forms, 
which  are  quite  characteristic  for  the  plants  in  which  they  are 
found.  They  may  have  the  form  of  transverse  or  oblique  rings, 


FIG.  132.  Phytomelane  in  root  of  Inula  Helenium.  1-3  showing  intercellular  spaces 
with  carbon-like  substance;  4-8,  striated  structure  of  intercellular  phytomelane  in  sections 
which  have  been  allowed  to  remain  in  solutions  of  hydrated  chloral  or  potassium  hydrate 
for  some  days;  9,  a  large  crystal-like  aggregate  in  a  schizogenous-like  reservoir  formed  in 
contiguous  intercellular  spaces  of  5  parenchyma  cells;  10,  separated  crystal-aggregates 
and  rod-shaped  masses  of  Phytomelane. — After  Senft. 

longitudinal  spirals,  or  may  be  ladder-like  or  reticulate  in  appear- 
ance (Figs.  141-144).  In  other  instances  the  thickening  of  the 
wall  is  quite  complex,  as  in  the  wood  of  the  pines  and  other  Conif- 
erse  (Fig.  68).  The  thickening,  or  sculpturing,  as  it  is  sometimes 


262  A  TEXT-BOOK  OF  BOTANY. 

called,  may  not  only  occur  on  the  inner  surface  of  the  wall,  when 
it  is  spoken  of  as  CENTRIPETAL,  but  may  also  take  place  on  the 
outer  surface,  when  it  is  known  as  CENTRIFUGAL,  as  in  the  spores 
of  lycopodium  and  the  pollen  grains  of  the  Compositse. 

FORMS  OF  CELLS. 

Upon  examining  sections  of  various  portions  of  the  plant,  it 
is  observed  that  not  only  do  the  cell-contents  and  cell-wall  vary 
in  composition,  but  that  the  cells  are  of  different  forms,  depend- 
ing more  or  less  upon  their  functions.  Groups  of  cells  which 
are  similar  in  form  and  function  constitute  the  various  tissues  of 
the  plant;  and  include:  (i)  parenchyma  cells,  (2)  mechanical 
cells,  (3)  conducting  cells,  and  (4)  protective  cells. 

Parenchyma. — Under  the  head  of  parenchyma  are  included 
those  cells  which  are  nearly  isodiametric  and  thin-walled,  the  walls 
consisting  of  cellulose  lamellae  (Fig.  134).  They  may  contain 
both  protoplasmic  and  non-protoplasmic  cell-contents.  Accord- 
ing to  the  function  and  nature  of  contents,  five  kinds  of  paren- 
chyma cells  are  recognized:  (a)  CHLOROPHYLL-PARENCHYMA  or 
assimilation  parenchyma  contains  numerous  chloroplastids  and 
occurs  in  leaves  and  all  green  parts  of  the  plant,  (b)  RESERVE 
PARENCHYMA  occurs  in  seeds,  roots,  rhizomes,  leaves,  and  contains 
starch,  aleurone  grains,  fixed  oils,  and  other  reserve  materials.  In 
some  instances  the  parenchyma,  as  in  the  endosperm  of  date, 
ivory  nut,  etc.,  may  be  very  thick-walled  (Fig.  135).  The  paren- 
chyma in  stems  and  leaves  of  various  of  the  orchids,  as  well  as 
that  of  plants  of  arid  regions,  which  store  water,  may  be  included 
in  this  group,  (c)  CONDUCTING  PARENCHYMA  is  found  either 
associated  with  the  sieve  or  with  the  tracheae,  the  cells  of  the 
phloem  conveying  the  plastic  substances,  while  those  of  the  xylem 
convey  water  and  salts.  The  cells  of  the  pith  and  cortex  are, 
as  a  rule,  not  utilized  for  the  rapid  translocation  of  food  materials 
to  far  distant  parts,  although  every  living  cell  and  every  tissue 
has  a  certain  power  of  translocation,  and  no  doubt  different 
parenchymatous  tissues  exhibit  varying  degrees  of  functional 
activity  and  differentiation.  Thus  large  quantities  of  reserve 
materials  are  rapidly  transferred  to  the  developing  embryo  through 
the  cells  of  the  endosperm,  and  in  young  seedlings  further  trans- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      263 

ference  probably  takes  place  mainly  through  the  cortical  and 
medullary  parenchyma,  (d)  SPONGY  PARENCHYMA,  or  loose, 
spongy  tissue  with  large  intercellular  spaces.  The  cells  of  this 


FIG.  133.  A  cell  from  sassafras  pith  showing  intercellular  space  (i);  middle  lamella 
(m);  layer  of  lignin  (1);  and  layer  of  cellulose  (c),  which  is  subsequently  modified  to  muci- 
lage; simple  pores  (p)  which  are  seen  in  the  lower  wall,  the  section  being  slightly  oblique. 
B,  portion  of  wall  showing  the  appearance  of  the  pores  when  the  view  is  transverse  to  the 
wall  and  the  focus  is  at  the  upper  part  of  the  pore  (a)  or  at  the  lower  part  (b). 

type  vary  from  slightly  branched  cells,  as  in  the  mesophyll  of 
leaves,  to  those  which  are  strongly  branched  and  stellate,  as  in 
Juncus,  Pondederia,  and  the  stems  of  various  marsh  plants.  In 


264 


A  TEXT-BOOK  OF  BOTANY. 


Calamus  the  cells  are  so  arranged  that  very  large  intercellular 
spaces  are  formed  (Fig.  134).  (e)  A  number  of  modifications 
of  typical  parenchyma  also  occur,  some  of  the  cells  being  either 
quite  thick-walled  or  considerably  elongated.  The  walls  of  pith- 

C 


FIG.  134.  Forms  of  cells.  A. — Transverse  section  of  the  pith  of  Tradescantia  vir- 
ginica:  I,  intercellular  space;  W,  cell  wall.  B. — Transverse  section  of  calamus  rhizome 
showing  a  large  oil-secretion  cell,  smaller  cells  containing  starch,  and  large  intercellular 
spaces  (I).  C. — Transverse  section  of  the  stem  of  Phytolacca  decandra  showing  collenchy- 
matous  cells  beneath  the  epidermis.  D. — Longitudinal  section  of  taraxacum  root  showing 
branched  laticiferous  tissue  (L).  E. — Transverse  section  of  pyrethrum  root:  R,  oil-secre- 
tion reservoir  with  oil  globules;  I,  cells  with  sphere-crystals  of  inulin,  such  as  separate  in 
alcoholic  material;  L,  cells  containing  irregular  masses  of  inulin,  as  found  in  dried  material. 
F. — Longitudinal  section  of  stem  of  Cucurbita  Pepo:  S,  sieve-cell  with  protoplasm-like 
contents,  and  transverse  walls  (sieve  plates)  showing  simple  pores. 

parenchyma  may  consist  of  lamellae  of  lignocellulose  and  mucilage, 
as  in  Sassafras  pith  (Fig.  133). 

MECHANICAL  TISSUE  includes  all  those  cells  which  serve  to 
keep  the  various  parts  of  the  plant  in  their  proper  positions,  one 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      265 

with  reference  to  the  other,  and  which  enable  it  to  withstand 
undue  strain  and  pressure.  There  are  two  principal  forms,  namely, 
(a)  collenchyma  and  (b)  sclerenchyma. 

THE  COLLENCHYMA  CELL  is  elongated,  prismatic,  with  soft 


FIG.  I3S.  A,  cells  of  endosperm  of  the  seed  of  the  date  palm  (Phoenix  dactylifera) ,  the 
one  normal  and  the  other  showing  the  stratification  of  the  wall  after  treatment  with 
chlor-zinc-iodide. 

B,  cell  of  endosperm  of  Phytelephas  macrocarpa  (vegetable  ivory)  showing  lamellation 
and  spherite  structure  in  the  wall  after  treatment  with  chlor-zinc-iodide,  clove  oil,  chromic 
acid  or  certain  other  reagents. 

C,  cell  of  endosperm  of  Strychnos  Nux-vomica  after  treatment  with  iodine  and  potas- 
sium iodide  solution. 

D,  opposite  pores  in  the  walls  in  contiguous  cells  of  vegetable  ivory  showing  striae 
between  them  after  treatment  with  iodine  solution. 

Walls  consisting  mainly  of  cellulose  and  never  lignified ;  the  contents 
being  rich  in  water.  In  transverse  section  it  is  readily  distin- 
guished by  the  local  thickening  of  the  walls,  i.e.,  at  the  angles  of 


266 


A  TEXT-BOOK  OF  BOTANY. 


the  cells  (Fig.  134,  c).  Pores  are  rare,  but  when  present  they 
are  annular  or  slit-like.  Collenchyma  occurs  near  the  surface 
of  plant  organs,  as  herbaceous  stems,  when  they  form  ribs,  as 


FIG.  136.  Various  forms  of  stone  cells:  A,  epidermis  of  hyoscyamus  seeds;  B, 
pericarp  of  pimenta,  containing  brownish  tannin  masses;  C,  seed-coat  of  coffee;  D,  seed-coat 
of  almond;  E,  transverse  section  of  seed-coat  of  white  mustard  showing  beaker  cells;  F, 
surface  view  of  beaker  cells  of  seed-coat  of  white  mustard;  G,  transverse  section  through 
stone  cells  of  endocarp  of  olive,  the  lumen  containing  air;  H,  a  stone  cell  from  the  periderm 
of  calumba,  containing  numerous  monoclinic  prisms  of  calcium  oxalate;  I,  various  forms 
of  stone  cells  isolated  from  pericarp  of  star  anise. 

in  the  Umbelliferse.    It  is  also  found  in  leaves  and  in  fruits,  as  in 
the  Umbelli ferae. 

SCLERENCHYMA  CELLS  include  all  of  those  cells  which  have 
more  or  less  uniformly  thickened  walls  composed  of  lignocellulose, 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       267 

permeated  by  simple  or  branching  pores.  They  have  a  thin  layer 
of  protoplasm  enclosing  large  vacuoles,  and  may  contain  tannin 
or  tannin-like  masses,  and  occasionally  calcium  oxalate  crystals 
or  starch,  and  in  dead  cells  the  lumen  or  cell  cavity  contains 
air.  Two  kinds  of  sclerenchyma  are  recognized:  i,  in  which  the 
cells  are  more  or  less  isodiametric  (Figs.  136-138),  known  as 
stone  cells  (short  sclerenchyma)  ;  and  2,  in  which  the  cells 
are  elongated  (Figs.  139-141),  being  from  0.5  to  2  mm.  in 
length  and  known  as  sclerenchymatous  fibers  (or  long  scleren- 
chyma). Of  these  latter,  two  kinds  are  distinguished,  chiefly 
according  to  their  position  in  the  plant,  namely,  bast  fibers,  or 
stereome,  and  wood  fibers,  or  libriform.  Seldom  are  the  wood  and 


FIG.  137.     Several  forms  of  stone  cells:     A,  white  oak  bark;    B,  white  cinnamon  or 
canella  bark  (Canella  alba);   C,  seed-coat  of  capsicum. 

bast  fibers  in  the  same  plant  uniform  in  structure  and  composition, 
as  in  glycyrrhiza  and  althaea.  On  the  other  hand,  they  are  with 
difficulty  distinguished  in  monocotyledonous  roots,  and  the  term 
sclerenchymatous  fiber  is  here  best  employed  to  include  both  kinds 
of  cells.  In  the  study  of  powdered  drugs  the  term  sclerenchyma- 
tous fiber  may  be  employed  with  advantage  when  speaking  O'f  wood 
and  bast  fibers,  as  in  this  condition  they  are  not  readily  distinguish- 
able. It  is  usual  in  plant  anatomy  to  include  as  stereome  all  ligni- 
fied  fibers  not  directly  associated  with  the  vessels  of  the  mestome 
strands  (or  vascular  bundles). 

STONE  CELLS  or  SCLEROTIC  CELLS  are  parenchymatous  cells 
with  very  thick,  lignified  walls,  composed  of  numerous  lamellae, 


268 


A  TEXT-BOOK  OF  BOTANY. 


which  are  permeated  with  simple  and  not  infrequently  branching 
pores.  They  vary  in  form,  being  usually  polygonal,  or  more  or 
less  irregular  in  outline,  sometimes  branching.  The  lamellation  of 
the  walls  is  brought  out  by  the  use  of  swelling  reagents,  as  solu- 
tions of  the  alkalies,  hydrated  chloral,  chromic  acid,  etc.  In 
typical  stone  cells  the  walls  always  give  the  characteristic  re- 
action for  lignocellulose  with  acid  solutions  of  either  phloro- 
glucin  or  aniline  sulphate.  The  lumina  of  the  cells  frequently 
contains  a  reddish,  amorphous  substance,  seldom  are  crystals  of 
calcium  oxalate  present  (Fig.  136,  //),  and  not  infrequently  they 
are  filled  with  air  (Fig.  136,  G).  In  the  identification  of  com- 


FIG.  138.    Various  forms  of  stone  cells  in  star  anise,  the  fruit  of  Ilhciunt  anisatum. 

mercial  products  the  study  of  the  contents  of  the  stone  cells  is 
frequently  as  important  as  that  of  the  forms  of  cells. 

BAST  FIBERS  or  STEREOMATIC  CELLS  are  sclerenchymatous 
fibers,  occurring  in  the  bark  and  usually  associated  with  sieve  cells. 
They  represent  the  skeleton  of  plants  and  are  the  most  important 
mechanical  tissues  of  the  bark,  being  much  firmer  than  the  collen- 
chyma.  They  are  very  long,  spindle-shaped,  with  more  or  less 
thick  walls,  and  provided  with  slit-like,  oblique  pores.  The  walls 
may  consist  of  cellulose,  as  in  the  fibers  of  flax,  but  they  are 
usually  more  or  less  lignified;  the  lumina  is  narrow  and  usually 
contains  air.  In  transverse  sections  the  fibers  are  more  or  less 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       269 

circular,  ellipsoidal  or  polygonal,  depending  upon  the  pressure 
upon  the  walls  and  whether  they  are  isolated  or  in  groups.  They 
vary  in  diameter  and  length,  and  also  in  the  thickness  of  the  walls ; 
while  most  bast  fibers  are  between  I  and  2  mm.  in  length,  they 
may  be  more  than  200  mm.  in  length,  as  in  Boehmeria  nivea. 
The  ends  may  be  more  or  less  obtuse  or  drawn  out  to  a  fine  point ; 


FIG.  139.  Transverse  (t)  and  longitudinal  (1)  sections  of  commercial  fibers:  A,  long 
staple  cotton  from  the  seeds  of  Gossypium;  B,  Kentucky  hemp,  the  bast  of  Cannabis 
sativa;  C,  jute,  the  bast  of  Corchorus;  D,  sisal,  the  fibers  from  the  leaves  of  the  Century 
plant  (Agave  rigida  Sisalana) ;  E,  raphia,  the  outer  layers  of  leaflets  of  Raphia.  pedunculata; 
F,  ramie,  the  fibers  from  a  Formosa  nettle;  G,  Merino  wool;  H,  silk;  I,  artificial  silk,  the 
figure  on  the  left  showing  a  false  lumen  due  to  the  infolding  of  the  edges,  f,  fungal  hyphae; 
c,  rosette  aggregates  of  calcium  oxalate;  p,  parenchyma  cells. 

occasionally  they  are  somewhat  branched  (Fig.  140).  The  pores 
in  surface  view  are  narrow  elliptical  and  arranged  according  to  a 
left-handed  spiral.  The  spiral  arrangement  of  the  component 
elements  of  the  wall  is  supposed  to  give  strength  to  the  fibers, 
and,  according  to  Schwendener,  they  will  sustain  a  weight  nearly 
equivalent  to  that  of  wrought-iron  and  steel. 


270 


A  TEXT-BOOK  OF  BOTANY. 


Bast  fibers  may  be  isolated  by  the  use  of  Schulze's  macerating 
fluid  (which  is  prepared  by  dissolving  a  few  crystals  of  potassium 
chlorate  in  nitric  acid)  and  moderately  heating  the  solution  con- 
taining the  material  either  on  a  slide  or  in  a  test-tube. 

The  mechanical  tissue  consisting  of  cells  resembling  bast  fibers 
and  occurring  in  leaves  and  fruits  is  usually  referred  to  as 
stereome. 

WOOD  FIBERS  or  LIBRIFORM  CELLS  are  sclerenchymatous  fibers 


1 


( / 


1  •  r '  i ?  *!  1 1  f . 


i 


FIG.  140.  A,  C,  bast  fibers  of  the  bark  of  Cinchona  succirubra;  B,  bast  fibers  of  the 
bark  of  Cinchona  Ledgeriana;  D,  stone  cells  of  Cuprea  bark  (Remijia  peduncuiata) . — After 
Oesterle  and  Tschirch. 

occurring  in  the  wood  and  are  usually  associated  with  the  tracheae. 
They  are  scarcely  to  be  distinguished  from  the  bast  fibers  except 
by  their  position,  and  are  the  strengthening  cells  of  the  xylem. 
While  the  bast  fiber  is  frequently  not  lignified,  the  walls  of  the 
wood  fibers  usually  consist  of  lignocellulose,  and  usually  give 
quite  pronounced  color  reactions  with  acid  solutions  of  either 
phloroglucin  or  aniline  sulphate.  Wood  fibers  are  usually  more 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       271 

abundant  than  bast  fibers  in  the  same  plant,  and,  while  the  bast 
fibers  may  be  wanting,  the  wood  fibers,  with  few  exceptions,  are 
always  present.  Wood  fibers  seldom  attain  the  length  of  bast 


BF 


FIG.  141.  Longitudinal-transverse  section  of  licorice  rhizome  including  the  cambium: 
P,  parenchyma;  T,  tracheae  or  ducts;  WF,  wood  fibers;  C,  cambium;  S,  sieve;  CF,  crystal 
fibers;  BF,  bast  fibers;  MR,  medullary  ray. 

fibers.  They  are  not  infrequently  branched  at  the  ends,  and, 
besides  a  thin  protoplasmic  layer,  they  usually  have  no  other 
contents  than  water  or  air.  They  frequently  have  yellowish 
walls,  characteristic  of  stone  cells,  and  also  exhibit  a  similar 
lamellation  and  refraction  of  the  wall. 


272 


A  TEXT-BOOK  OF  BOTANY. 


Conducting  cells  or  mestome  include  those  cells  which  are 
chiefly  concerned  in  the  transferral  of  either  crude  or  assimilable 


FIG.  142.  Development  of  spiral  bands  in  the  mechanical  cells  of  young  fruits  of  Fegatella 
conica  (Hepaticse):  I,  young  cell  with  vacuoles  and  small  starch  grains;  II,  portion  of  an  older 
cell  showing  formation  of  large  vacuoles  in  the  protoplasm,  the  strands  of  which  are  arranged 
in  a  left-hand  spiral;  III,  showing  spiral  arrangement  of  protoplasm;  IV,  portion  of  cell 
as  in  III  treated  with  a  sugar  solution  and  showing  plasmolysis  of  protoplast;  V,  showing 
formation  of  band;  VI,  a  cell  as  in  V  treated  with  sugar  solution,  showing  the  protoplasm 
arranged  along  the  thickened  portions  of  the  wall  where  the  bands  are  forming;  VII,  the 
mature  cell  showing  lignified  spiral  bands. — After  Dippel  in  "Das  Mikroskop." 

food  materials.    The  more  or  less  crude  inorganic  materials  are 
carried  from  the  root  through  the  woody  portion  of  the  stem  to 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      273 


the  leaves,  and  from  the  leaves  the  products  of  photosynthesis, 
as  well  as  other  plastic  substances,  are  distributed  through  some 
of  the  tissues  of  the  bark  to  other  parts  of  the  plant.  The  tissues 
or  elements  of  the  wood  which  conduct  food  materials  are  of  sev- 
eral forms  and  include  tracheae  or  vessels  (also  called  "  ducts  "), 
tracheids,  and  conducting  parenchyma ;  and  the  elements  of  the 
bark  which  transport  the  assimilable  materials  comprise  the  lep- 
tome  and  conducting  parenchyma  (Fig.  141).  Water-conducting 
elements  (TRACHEAL  ELEMENTS)  comprise  the  vessels  (tracheae) 
and  the  tracheids,  which  resemble  each  other,  except  that  the  latter 
are  single  cells  of  prosenchymatic  shape,  while  the  former  are 
very  long  tubes,  varying  from  cylindrical  to  prismatic  in  shape,  and 
consist  of  long  rows  of  cells  which  are  superimposed  length- 
wise, the  transverse  walls  being  usually  obliterated. 

S  D  C_     _R 


FIG.  143.  Forms  of  tracheae  or  vessels.  A. — Longitudinal  section  of  stem  of  Cucurbita 
Pepo  showing  various  forms  of  tracheae:  A,  annular;  S,  spiral;  D,  double  spiral;  C,  close 
annular;  R,  reticulate.  B. — Tracheae  in  glycyrrhiza  rhizome :  W,  wall;  B,  bordered  pores; 
P,  oblique  simple  pores. 

The  tracheae  or  vessels  are  formed  by  the  disintegration  and 
removal  of  the  transverse  walls  between  certain  superimposed 
cells,  forming  an  elongated  cell  or  tube,  which  occasionally  retains 
some  of  the  transverse  walls  (Figs.  142-144).  The  longitudinal 
walls  are  relatively  thin  and  consist  of  lignocellulose,  giving  pro- 
nounced reactions  with  phloroglucin  or  aniline  sulphate. 

Four  types  of  vessels  or  tracheae  are  known :  annular,  spiral, 
reticulate,  and  porous.  Those  having  the  thickenings  in  the  form 
of  horizontal  or  oblique  rings  are  known  as  ANNULAR  TRACHEAE; 
those  having  the  thickenings  in  the  form  of  spirals,  which  usually 
run  from  right  to  left,  are  known  as  SPIRAL  TRACHEA;  those 
having  the  thickenings  in  the  form  of  a  reticulation  are  known  as 

18 


274 


A  TEXT-BOOK  OF  BOTANY. 


RETICULATED  TRACHEAE,  and  those  with  spherical  or  oblique  slit 

pores  are  known  as  POROUS  TRACHEAE  or  vessels  (Figs.  142-144). 

In  those  vessels  in  which  but  few  of  the  transverse  walls  are 

obliterated,  the  walls  are  marked  by  both  simple  and  bordered 


FIG.  144.  Types  of  tracheae  or  vessels.  A,  vessels  with  annular  and  spiral  thickenings 
in  Phlox  Carolina;  B,  longitudinal  section  through  fibrovascular  bundle  in  aconite,  showing 
porous  (p)  and  spiral  tracheae  (t),  bast  fibers  (b),  and  some  of  the  collenchyma  cells  (c); 
C,  longitudinal  section  showing  reticulate  tracheae  in  scopolia;  D,  longitudinal  section  of 
the  woody  part  of  the  rhizome  of  Spigelia,  showing  tracheae  (t) ,  tracheids  (h) ,  tracheae  (r) 
with  yellowish-brown,  gum-like  masses;  E,  portion  of  xylem  of  stem  showing  in  Hyos- 
cyamus  tracheae  (t)  with  bordered  pores  and  wood  fibers  (w),  with  simple  oblique  pores. 

,pores,  which  latter  are  described  under  tracheids.  Vessels  contain 
water,  water- vapor,  and  air;  in  some  cases  they  contain  sugar, 
tannin,  mucilage,  or  resin. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       275 


The  tracheids  are  intermediate  in  character  between  tracheae 
and  libriform,  resembling  the  former  in  possessing  bordered  pores 
(Fig.  145)  and  scalariform  thickenings;  and  the  latter  in  being 
true  cells,  which  are  usually  elongated  and  quite  thick-walled, 
the  walls  giving  distinct  reactions  for  lignocellulose  with  phloro- 
glucin  or  aniline  sulphate. 

One  of  the  chief  characteristics  of  tracheids  is  the  BORDERED 
PORES  (Fig.  145).  These  differ  from  simple  pores  in  that  the 
wall  surrounding  the  pore  forms  a  dome-shaped  or  blister-like 


FIG.  145.  Bordered  pores  of  the  tracheids  of  the  wood  of  Abies  alba  as  viewed  in 
longitudinal  section:  m,  middle  lamella;  v,  i,  middle  and  inner  layers  of  walls  of  contigu- 
ous cells  ;  C,  pore-canal  through  which  sap  passes  from  one  cell  to  another ;  L,  dome- 
shaped  cavity  of  pore;  S,  separating  wall  or  closing  membrane  which  is  usually  thickened 
in  the  middle  as  shown  at  t.  In  older  cells  the  separating  membrane  is  broken  as  shown 
in  the  lower  pore  in  figure  2.  At  the  right  in  figure  4  is  shown  a  surf  ace  view  of  a  bordered 
pore,  the  dotted  lines  indicating  the  relation  of  the  circles  to  the  structure  of  the  pore. — 
After  Vogl. 

protrusion  into  the  cell.  On  surface  view  the  pores  are  either 
circular  or  elliptical  in  outline,  the  dome  being  circular  or,  if  the 
pores  are  numerous  and  arranged  close  together,  more  or  less 
polygonal  (Figs.  143,  144). 

The  number  and  distribution  of  bordered  pores  in  the  Coni- 
ferae  are  quite  characteristic  for  some  of  the  genera,  and  may  be 
studied  in  any  of  the  pines,  the  pores  being  most  numerous  in 
the  radial  walls  (Fig.  69). 


276 


A  TEXT-BOOK  OF  BOTANY. 


The  leptome  or  sieve  is  distinguished  from  the  other  con- 
ducting elements  in  that  the  walls  are  thin  and  are  composed  of 
cellulose  (Fig.  146).  It  consists  of  superimposed  elongated  cells, 
the  transverse  walls  of  which  possess  numerous  pores  which  are 
supposed  to  be  in  the  nature  of  openings,  permitting  of  the 


in 


FIG.  146.  Different  forms  of  sieve  pores:  I,  portion  of  sieve  tube  of  Bryonia  alba, 
II  of  Cucurbita  Pepo,  A  longitudinal  section  and  B  in  transverse  section;  III,  portion  of  a 
sieve  cell  of  Larix  europcea  showing  round  sieve  pores;  IV,  an  old  sieve  plate  in  Bryonia 
alba  treated  with  chlor-zinc-iodide,  showing  the  striated  callous  plates  (c),  (z)  cell-wall, 
(s)  sieve  plate,  (i)  contents  of  sieve  tube,  (h)  cell  membrane,  (c)  callous  plates. — After  Dippel 
in  "Das  Mikroskop." 

direct  passage  of  the  contents  from  one  cell  to  the  other.  This 
transverse  wall,  which  may  be  either  horizontal  or  oblique,  is 
known  as  the  SIEVE  PLATE,  and  the  thin  places  as  pores  of  the 
sieve.  The  sieve  plates  are  sometimes  also  formed  on  the  longi- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       277 

tudinal  walls.  When  the  activities  of  plants  are  suspended  during 
the  winter,  there  is  formed  on  either  side  of  the  sieve  plates  a  layer 
of  a  colorless,  mucilaginous  substance,  known  as  callus,  which  has 
somewhat  the  appearance  of  collenchyma,  but  is  colored  brownish 
by  chlor-zinc  iodide. 

The  sieve  cells  contain  an  albuminous  substance  somewhat 
resembling  protoplasm ;  in  some  instances  starch  grains  have  also 
been  found. 

When  the  activities  of  the  sieve  tubes  have  ceased,  they  be- 
come altered  in  shape,  and  are  then  known  as  altered  sieve.  In 
the  drying  of  plants  a  similar  alteration  is  produced,  and  the 
sieve  of  vegetable  drugs  is  referred  to  as  "  obliterated  "  sieve. 

Protecting  cells  include  those  cells  which  are  located  on  the 
outer  parts  of  the  plant.  The  function  of  these  cells  is  to  lessen 
the  rate  of  transpiration,  or  the  giving  off  of  water ;  to  furnish 
protection  against  changes  of  temperature,  and  to  protect  the 
inner  tissues  against  the  attack  of  fungi  and  insects  ;  they  also  have 
a  mechanical  function  (Figs.  147,  157). 

Depending  principally  upon  their  composition,  these  cells  may 
be  divided  into  two  classes,  namely,  epidermal  cells  and  cork  cells. 

The  epidermal  cells  constitute  the  outermost  layer  of  the 
plant.  They  contain  cytoplasm,  but  the  plastids  in  some  instances 
are  wanting;  in  petals,  etc.,  they  also  contain  dissolved  color- 
ing principles ;  and  on  account  of  the  relatively  large  amount  of 
water  which  they  contain  they  are  classed  among  the  important 
water-reservoirs  of  the  plant. 

The  outer  walls  are  principally  characterized  by  one  or  more 
lamellae  of  cutin,  these  uniting  to  form  a  continuous  wall.  The 
cutin  is  often  associated  with  wax,  this  constituting  the  bloom  of 
fruits ;  less  frequently  such  inorganic  substances  as  calcium  car- 
bonate, calcium  oxalate,  and  silica  are  present,  and  not  infre- 
quently mucilage  is  present,  as  in  the  walls  of  certain  seeds  (Fig. 

119,  ^)- 

On  surface  view  the  form  of  these  cells  varies  from  nearly 
isodiametric  to  oblong;  they  may  also  be  polygonal  or  branched. 
In  transverse  section  their  radial  diameter  is  much  the  shorter. 
In  some  instances  the  inner  and  side  walls  are  considerably  thick- 
ened, as  in  the  seeds  of  a  number  of  the  Solanaceae  (Fig.  136,  A). 


278 


A  TEXT-BOOK  OF  BOTANY. 


The  epidermis  usually  consists  of  a  single  layer  of  cells,  but 
may  have  additional  layers  underneath  forming  the  HYPODERMIS, 
as  in  the  upper  surface  of  the  leaves  of  species  of  Ficus  (Fig.  113)  ; 


PIG.  147.  Stomata  and  water-pores.  A. — Transverse  section  through  lower  surface 
of  leaf  of  stramonium:  stoma,  with  guard  cells  (G),  containing  cytoplasm,  nucleus  and 
chloroplastids;  N,  surrounding  cells;  A,  intercellular  cavity  usually  filled  with  cell-sap  or 
watery  vapor;  E,  epidermal  cells;  M,  mesophyll.  B. — Surface  section  of  upper  surface  of 
leaf  of  Viola  tricolor  showing  four  stomata.  C. — Surface  section  of  under  surface  of  leaf  of 
Viola  tricolor  showing  five  stomata.  D. — A  section  through  the  margin  of  the  leaf  of  Viola 
tricolor  showing  a  tooth  with  three  water-pores.  E. — A  water-pore  of  Viola  tricolor  in 
surface  section. 

in  some  instances  the  hypodermis  undergoes  a  mucilage  modifica- 
tion, as  in  the  leaves  of  buchu. 

Stomata. — Distributed  among  the  epidermal  cells  are  pairs 
of  crescent-shaped  cells  known  as  a  STOMA,  and  having  an  open- 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       279 

ing  or  pore  between  them,  which  leads  to  a  cavity  beneath  it.  The 
two  cells  of  the  stoma  are  known  as  GUARD  CELLS  (Fig.  147,  G). 
The  adjoining  walls  of  the  guard  cells  are  alike  in  transverse  sec- 
tion, but  the  cells  vary  in  shape  in  different  plants.  The  guard 
cells  are  more  or  less  elastic,  and  when  the  cells  are  turgescent,  as 
when  there  is  an  abundance  of  water  and  root  pressure  is  strongest, 
the  contiguous  walls  of  the  cells  recede  from  each  other,  forming 
an  opening  between  them,  thus  permitting  the  exit  of  the  excess  of 
water  taken  up  by  the  plant  and  the  exhalation  of  the  oxygen 
given  off  during  assimilation,  as  well  as  the  intake  of  the  carbon 
dioxide  used  in  photosynthesis.  On  the  other  hand,  when  the 
amount  of  water  in  the  plant  is  reduced  below  the  normal  and  the 
plant  shows  signs  of  wilting  the  guard  cells  flatten  and  the  open- 
ing or  pore  is  closed  (Fig.  214).  The  cells  beneath  the  stoma  are 
loosely  arranged,  so  that  the  air  containing  carbon  dioxide  may 
be  readily  diffused  to  the  cells  containing  the  chloroplastids. 

The  guard  cells  may  be  slightly  raised  above  or  sunk  below 
the  surrounding  epidermal  cells,  the  number  of  the  latter  being 
characteristic  for  certain  plants.  (Compare  Figs.  147,  211-218.) 

Stomata  occur  in  the  largest  numbers  on  the  blades  of  foliage 
leaves,  being  more  numerous  on  the  under  surface,  except  in 
aquatic  plants,  where  they  occur  only  upon  the  upper  surface. 

Water  Pores. — Near  the  margin  of  the  leaf  and  directly  over 
the  ends  of  conducting  cells,  not  infrequently  occur  stomata,  in 
which  the  function  of  opening  and  closing  is  wanting,  and  which 
contain  in  the  cavity  below  the  opening  water  and  not  air,  thus 
differing  from  true  stomata  (Fig.  147,  D,  E).  These  are  known 
as  WATER  PORES,  and  they  give  off  water  in  the  liquid  form,  the 
drops  being  visible  on  the  edges  of  the  leaves  of  nasturtiums, 
fuchsias,  roses,  etc.,  at  certain  times. 

Plant  Hairs. — The  epidermal  cells  are  sometimes  specially 
modified  centrifugally,  giving  rise  to  papillae,  to  which  the  velvety 
appearance  of  the  petals  of  flowers  is  due;  in  other  cases  this 
modification  is  in  the  form  of  hairs  or  trichomes  (Figs.  148-155). 
These  may  be  unicellular  or  multicellular,  and  in  addition  the 
latter  may  be  glandular  or  non-glandular.  Glandular  hairs  possess 
a  head-like  apex,  consisting  of  one  or  more  cells,  and  they  secrete 
oil,  mucilage,  and  other  substances  (Figs.  124,  125,  149,  150). 


A  TEXT-BOOK  OF  BOTANY. 


In  the  examination  of  technical  products,  as  also  in  taxonomic 
work,  the  study  of  plant  hairs  is  very  important.  They  show  a 
great  diversity  in  form  in  not  only  genera  and  families  but  even 
in  related  species.  They  vary  considerably  in  their  distribution 


FIG.  148.  Mostly  non-glandular  hairs  and  a  few  of  the  small  glandular  hairs  covering 
the  surface  of  the  fruits  of  several  species  of  Rhus:  g,  hairs  on  Rhus  glabra,  being  more  or 
less  broadly  top-shaped  or  carrot-shape  to  spatulate  and  occasionally  narrow  elliptical  and 
from  o.ioo  to  0.400  mm.  in  length;  b,  hairs  on  Rhus  typhina,  being  long  and  needle-like, 
varying  from  0.750  to  1.500  mm.  in  length;  c,  hairs  of  Rhus  glabra  borealis,  being  intermedi- 
ate between  those  of  Rhus  glabra  and  Rhus  typhina,  varying  from  elongate  spatulate  and 
narrow  cylindrical  to  needle-shaped,  and  from  o.ioo  to  i.ooo  mm.  in  length. 

not  only  in  related  species,  but  sometimes  in  varieties  of  the  same 
species  they  show  marked  variation  in  size  and  form.  In  some 
natural  hybrids  intermediate  forms  of  hairs  of  the  parent  species 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      281 

are  found.  This  was  pointed  out  by  Kraemer  in  some  studies 
on  Rhus  glabra  and  Rhus  typhina  (Amer.  Jour.  Pharm.,  1913, 
p.  404),  in  which  a  herbarium  specimen  in  the  New  York  Botanical 
Garden  and  labelled  by  Britton  as  Rims  glabra  borealis  shows 
hairs  which  in  form  and  size  are  intermediate  between  those  of 
R.  glabra  and  R.  typhina  (Fig.  148). 

Plant  hairs  may  be  divided  into  two  principal  groups:  I. 
GLANDULAR  HAIRS,  or  those  in  which  the  summit  consists  of  one 
or  more  cells  which  secrete  beneath  the  cuticle  either  mucilage, 
oils,  or  oleo-resins,  and  the  summit  of  the  hair  possesses  a  more 
or  less  globular  form.  II.  NON-GLANDULAR  HAIRS,  or  those  in 
which  the  summit  of  the  hair  consists  of  one  or  more  rounded  or 
pointed  cells  in  which  no  secretion  is  formed  beneath  the  cuticle. 

GLANDULAR  HAIRS  may  be  divided  into  five  different  groups : 

1.  Unicellular   glandular   hairs    consist   of    a    single   tubular 
cell,  the  upper  portion  being  more  or  less  swollen  and  rounded 
(Fig.  149,  A,  B).    Hairs  of  this  type  occur  in  the  Euphorbiaceae, 
in  which  they  more  or  less  resemble  Papillae.    In  the  Compositae 
they  contain  a  latex  and  appear  to  be  connected  with  the  laticif  er- 
ous  vessels.     They  also  occur  in  the  Anacardiaceae,  Cornaceae, 
Geraniaceae,  Leguminosae,  Malvaceae,  Menispermaceae,  Onagraceae, 
Piperaceae,  Ranunculaceae,  Tiliaceae  and  Zygophyllaceae. 

2.  Multicellular  glandular  hairs  consist  of  a  number  of  forms  ; 
either  they  are  differentiated  into  a  stalk  and  a  head,  or  the  stalk 
may  be  wanting  when  the  hair  has  a  spatulate  or  clavate  form. 
These  are  often  very  characteristic  for  certain  families,  as  the 
glandular  hairs  in  the  Labiatae  (Fig.  124),  which  possess  a  short 
stalk,  and  a  head  portion  with  eight  cells,  the  cuticle  being  raised 
like  a  bladder  owing  to  the  great  accumulation  of  secretion.    There 
are  a  great  many  types  of  multicellular  glandular  hairs  (Fig.  149). 
They  may  be  uniseriate,  i.e.,  consisting  of  a  series  of  cells  with 
either  a  unicellular  head  (Fig.  149,  C,  E,  K,  M),  as  in  the  Meni- 
spermaceae, Araliaceae,   Malvaceae,   Caryophyllaceae,   Geraniaceae, 
etc.,  or  they  may  be  bicellular  (Fig.  149,  D,  F,  H,  J,  L,  0),  as  in 
the  Cruciferae.    The  heads  may  consist  of  two  to  four  cells  (Fig. 
149,  G,  V ,  Y),  as  in  the  Burseraceae,  or  eight  cells,  as  in  the  Labiatae 
(Fig.  149,  W).    Multicellular  glandular  hairs  have  been  found  in 
the  following  families:   Aceraceae,  Anacardiaceae,  Araliaceae,  Be- 


282 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  149.  Various  types  of  glandular  hairs.  Unicellular  hairs  on  Julocroton  fus- 
cescens  (A),  Croton  monanthogynus  (B).  Uniseriate  uni-glandular  hairs  on  Zollikoferia 
nudicaulis  (C),  Silene  villosa  (E),  Geranium  favosum  (K),  Boerhaavia  repens  (M).  Glandular 
hairs  with  two-celled  heads  on  Hesperis  glutinosa  (D),  Pityrodia  salvifolia  (F),  Cyclamen 
persicum  (H),  Lysimachia  Nummularia  (]),  Chenopodium  Botrys  (L),  Diospyros  Kaki  (O). 
Glandular  hairs  with  four-celled  heads  on  Humulus  Lupulus  (G),  Boswellia  papyrifera  (V), 
Humulus  Lupulus  (Y).  Glandular  hairs  with  five-celled  heads  on  Combretum  aculeatum  (Z), 
Humulus  Lupulus  (Y).  Glandular  hairs  with  six-celled  heads  on  Rhododendron  Dalhousia 
(X),  hair  characteristic  on  the  Phaseolece  (U).  Glandular  hairs  with  eight-celled  heads  on 
•Lavandula  vera  (W).  Glandular  hairs  with  multicellular  heads  on  Pieris  floribunda  (N), 
Begonia  carolinicefolia  (S),  Begonia  pretoniensis  (s).  Glandular  hairs  with  four  and  eight 
cells  respectively  on  Picramnia  coccinea  (P).  Glandular  hairs  with  two  and  four  cells  re- 
spectively on  Cistus  ladaniferus  (R).  Double  glandular  hair  on  Rhododendron  lanatum  (T) 
— Adapted  from  Solereder  and  redrawn  by  Hogstad. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       283 

goniaceae,  Berberidacese,  Bixaceae,  Borraginaceae,  Burseraceae. 
Capparidaceae,  Caprifoliaceae,  Caryopyhllaceae,  Chenopodiaceae, 
Combretaceae,  Compositae,  Convolvulaceae,  Cornaceae,  Crassulaceae, 
Cruciferae,  Cucurbitaceae,  Dipsaceae,  Ericaceae,  Euphorbiaceae, 
Fagaceae,  Geraniaceae,  Hippocastanaceae,  Hydrophyllaceae,  Labi- 
atae,  Leguminosae,  Malvaceae,  Melastomataceae,  Meliaceae,  Meni- 
spermaceae,  Moraceae,  Myrsinaceae,  Nolanaceae,  Nyctaginaceae, 
Nymphaeaceae,  Piperaceae,  Platanaceae.  Plantaginaceae,  Polemoni- 
aceae,  Polygonaceae,  Portulacaceae,  Primulaceae,  Rosaceae,  Ru- 
taceae,  Sapindaceae,  Saxifragaceae,  Scrophulariaceae,  Simarubaceae, 
Solanaceae,  Sterculiaceae,  Theaceae,  Tiliaceae,  Umbelli ferae,  Ul- 
maceae,  and  Valerianaceae. 

3.  Glandular  leaf-teeth,  as  the  name  would  signify,  include 
the    glandular    hairs   formed  on  the  lobes  of  leaves.     They  vary 
in  structure  and  may  secrete  mucilage,  as  in  the  Violaceae  (Fig. 
120)  and  in  some  of  the  Compositae,  or  they  may  secrete,  in  addi- 
tion,  resin,   as  in  the  Rosaceae,  or  calcium  oxalate,  as  in  the 
Saxifragaceae. 

4.  Special   forms   of   multicellular  glands   are   found   in   the 
Aceraceae,  in  which  a  pair  of  glands  are  fused  together.    In  some 
of  the  Compositae  and  Moraceae  a  group  of  glandular  hairs  are 
united.     Other  special  types  also  occur  in  the  Droseraceae,  Ana- 
cardiaceae,  Leguminosae,  etc. 

5.  Hair-like  external  glands  having  a  complicated  structure 
have  been  observed  in  a  number  of  families.     They  are  limited 
to  certain  portions  of  the  plant,  being  found  in  the  Apocynaceae 
at  the  base  of  the  leaves  and  in  the  Rubiaceae  only  on  the  stipules. 
They  are  usually  very  large,  secreting  considerable  mucilage  and 
resin.     The  glandular,  shaggy  hairs  occurring  on  the  stipules  in 
the  Rubiaceae  are  of  this  type,  the  secretion  being  often  so  abundant 
that  the  young  leaves   emerging   from  the   stipular  sheath   are 
coated  with  this  resin,  which  is  even  retained  by  the  mature 
leaves. 

II.  NON-GLANDULAR  HAIRS  are  of  three  general  types:  I. 
Simple  hairs  (Figs.  148,  151),  which  may  be  unicellular  or  uni- 
seriate, — i.e.,  consisting  of  a  series  of  superimposed  cells.  2. 
Peltate  or  stellate  groups  (Fig.  153,  D,  E,  H,  K},  consisting  of 
two  or  more  hairs  united  at  the  base  and  spreading  like  a  star. 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  150.  Forms  of  glandular  hairs:  A,  corkscrew-like  hairs  from  the  inner  surface 
of  the  spurred  corolla  of  lavender;  B,  longitudinal  section  of  rhizome  of  Dryopteris  mar- 
ginalis  showing  large  intercellular  space  and  an  internal  oil-secretion  hair;  C,  hairs  from 
stramonium  leaf;  D,  hairs  from  Digitalis;  E,  hair  from  sage;  F,  hair  from  eriodictyon;  G. 
hairs  from  inner  walls  of  pericarp  of  vanilla;  H,  hair  from  cannabis  indica;  I,  hairs  from 
surface  of  fruit  of  Rhus  glabra;  K,  hairs  from  belladonna  leaf. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       285 

These  may  consist  of  one  or  more  series  of  cells,  separated  by  a 
columnar  cell.  3.  Shaggy  hairs  (Fig.  153,  G),  in  which  the 
epidermal  layer  of  the  column  of  cells  is  modified  to  papillae 


PIG.  151.     Forms  of  non-glandular  hairs:    A,  hair  from  the  epidermis  of  strophanthus; 

B,  a  hair  from  the  capsule  of  Mallotus  philippinensis  (found  in  the  drug  known  as  kamala) ; 

C,  hairs  from  the  leaves  and  bracts  of  cannabis  indica,  two  of  them  containing  cystoliths 
of  calcium  carbonate;    D,  a  hair  from  the  under  surface  of  the  leaf  of  senna;  E,  hairs  from 
leaf  of  digitalis;   F,  two  forms  of  hairs  from  sage  leaf;   G,  two  forms  of  hairs  from  the  leaves 
of  wormwood  (Artemisia  Absinthium):  a  T-shaped  non-glandular  hair  and  a  short  glandular 
hair. 

which  are  directed  upwards,  giving  the  surface  of  the  plant  the 
appearance  of  being  covered  with  rough  hairs  or  wool. 

Non-glandular  hairs  occur  on  a  large  number  of  plants.    They 


286 


A  TEXT-BOOK  OF  BOTANY. 


vary  in  form  and  are  very  characteristic  in  a  great  many  plants. 
The  terms  used  to  describe  the  various  types  of  hairs  are  in  a 
few  instances  rather  simple,  but  there  are  so  many  modifications 
that  nothing  short  of  an  illustration  will  suffice  to  define  them. 
The  simple  hairs  may  be  divided  into  a  number  of  sub-divisions : 
(a)  Papillose  hairs,  being  short  outgrowths  of  the  epidermal  cells, 
somewhat  resembling  the  papillae  found  on  the  ventral  surfaces  of 
petals.  This  form  is  found  in  a  relatively  few  families,  (b) 
Unicellular  hairs,  being  outgrowths  considerably  longer  than 
papillae  and  occur  in  a  large  number  of  plants.  This  is  also  true 
of  a  third  type  (c),  known  as  uniseriate  hairs  and  in  which  there 


B 


G 


FIG.  152.  Forms  of  non-glandular  hairs:  A,  twisted  hairs  from  under  surface  of 
leaf  of  eriodictyon;  B,  lignified  hairs  from  the  epidermis  of  nux  vomica;  C,  branching 
hairs  from  the  leaf  of  mullein  (Verbascum  thapsus). 

are  two  or  more  cells  connected  as  in  a  chain.  Among  special 
terms  frequently  used  the  following  may  be  mentioned:  (d) 
Hooked  hairs  (Fig.  i$^,A,B),  in  which  the  summit  is  bent  in  the 
form  of  a  hook,  (e)  Two-armed  hairs  (Fig.  153,  D),  in  which 
the  summit  consists  of  two  cells  which  diverge  from  each  other 
and  spread  out  horizontally  or  parallel  to  the  surface  of  the  leaf. 
(/)  Stellate  hairs  (Fig.  151,  B)  consist  of  a  group  of  cells  ar- 
ranged around  a  simple  point,  as  in  the  Cruciferae  and  Saxifra- 
gacese.  (g)  Peltate  hairs  (Fig.  153,  E)  consist  of  a  group  of 
radially  arranged  cells,  of  which  all  or  only  some  reach  the  centre 
of  the  shield,  as  in  the  Solanaceae,  Malvaceae,  Loganiacese,  and 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      287 

Rosaceae.  (h)  Candelabra  or  abietiform  hairs  (Fig.  153,  L)  are 
those  which  have  a  uniseriate  main  axis,  interrupted  at  intervals 
by  whorls  of  ray  cells.  These  show  considerable  variation  and  are 
very  characteristic  in  the  Solanacese,  Acanthaceae,  Leguminosae, 
Labiatae,  and  Euphorbiaceae.  (i)  Stinging  hairs  (Fig.  153,  /), 
or  those  containing  an  irritating  substance,  as  in  the  stinging  nettle 
and  other  plants  of  the  Urticaceae.  The  hairs  are  rather  long,  the 


-TIL 

FIG.  153.  Several  types  of  non-glandular  hairs.  Crystal  hairs  on  Malanea  macro- 
Phylla:  A,  showing  hair  with  a  single  row  of  crystals;  B,  cell  with  2  rows  of  crystals;  C, 
transverse  section  of  B,  showing  crystals.  Two-armed  hairs  on  Artemisia  Absinthium  (D) 
and  Dichondra  repens  (II) ;  F,  uniseriate  non-glandular  hair  on  Pongamia  glabra;  E,  longi- 
tudinal view  showing  two  of  the  cells  of  a  peltate  hair  on  'Solatium  argenteum;  G,  shaggy 
hair  on  Calandrinia  umbellata;  J,  upper  portion  of  stinging  hairs  of  Urtica  dioica;  K,  cup- 
shaped  peltate  hair  on  Rhododendron  A  nthopogon;  L,  candelabra  hair  on  Verbascum  Thap- 
sus. — Adapted  from  Solereder  and  redrawn  by  Hogstad. 

summit  bearing  a  spherical  or  ovoid  head,  which  is  obliquely  in- 
serted and  rather  easily  detached,  thus  leading  to  the  emission  of 
the  contents.  The  stinging  sensation  was  formerly  stated  to  be 
due  to  formic  acid,  but  it  is  now  supposed  to  be  in  the  nature  of  a 
substance  related  to  the  ferments.  (/)  Crystal-containing  hairs. 
Calcium  oxalate  (Fig.  153,  A,  B,  C),  either  in  the  form  of  rosette 
aggregates  or  prisms  or  needles,  is  sometimes  present  in  the 


288 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  154.  Hairs  in  the  Compositae:  A,  slightly  curved  or  hooked  hairs  on  the  corolla 
of  Dandelion;  B,  hooked  hairs  on  the  filaments  of  Inula;  C,  hairs  on  pappus  of  Tragopogon 
pratensis;  D,  hair  from  akene  of  Tragopogon  pratensis;  E,  portion  of  barbed  hair  upon 
pappus  of  Inula;  F  and  G,  double  hairs  fromacheneof  Tagetes  tenuifolia;  H,  double  hairs 
from  achene  of  Inula;  J,  double  hair  from  corolla  of  Calendula. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.      289 


FlG.   155.     Characteristic    branching    hairs    found    on    the    stem,    leaves,    and    calyx    of 

Hyoscyamus  muticus. 

stinging  hairs  of  some  of  the  Euphorbiaceae,  as  well  as  in  some  of 
the  genera  of  the  Cornaceae,  Geraniaceae,  Rosacese,  and   Saxi- 
fragaceae. 
19 


290  A  TEXT-BOOK  OF  BOTANY. 

LIGNIFIED  HAIRS. — In  some  seeds,  as  in  nux  vomica,  the  hairs 
are  strongly  lignified,  as  are  also  the  bases  of  the  hairs  of  Stro- 
phantus  hispidus.  This  is  due  to  a  lignocellulose  modification  of 
the  wall,  and,  since  broken  hairs  look  more  or  less  like  fibers,  one 
might  easily  be  led  astray  in  the  study  of  powdered  drugs.  It  is 
not  usual  to  make  a  microchemical  study  of  the  walls  of  non- 
glandular  hairs,  but  this  subject  is  well  worthy  the  attention  of 
investigators. 

FALSE  PLANT  HAIRS. — While  it  is  impossible  for  the  careful 
student  of  plant  morphology  to  mistake  anything  else  for  plant 
hairs,  it  is,  nevertheless,  worth  while  to  call  attention  to  some  of 
the  mistakes  that  are  liable  to  be  made.  In  works  on  systematic 
botany  sometimes  occur  contradictory  statements  concerning  the 
abundance  or  scarcity  of  hairs,  especially  as  they  relate  to  the 
flower.  In  a  superficial  examination,  for  instance,  in  the  violets, 
large  masses  of  germinating  pollen  grains  with  their  tubes  matted 
together  are  not  at  all  uncommon  in  the  throat  of  the  corolla,  and 
these  have  been  mistaken  for  hairs.  Furthermore,  the  mycelia 
of  fungi  may  be  mistaken  for  hairs,  especially  in  young  seedlings, 
as  of  hyoscyamus,  belladonna,  etc.,  where  thread-like  delicate 
branching  hairs  may  occur.  In  the  examination  of  economic  prod- 
ucts, especially  powdered  drugs  and  spices,  mistakes  of  this  kind 
may  occur,  unless  the  student  has  devoted  some  attention  to  this 
study.  In  all  studies  of  plant  hairs  the  student  should  carefully 
locate  the  summits  and  bases,  and  unless  these  can  be  recognized, 
or  if  broken  made  to  correspond  to  each  other,  one  cannot  say 
that  hairs  are  present. 

CORK  CELLS  replace  the  epidermal  cells  of  roots  and  stems  that 
persist  year  after  year.  They  are  formed,  as  has  already  been 
stated,  from  a  distinct  meristem,  called  the  phellogen.  Cork  cells 
differ  from  the  epidermal  cells  in  that  the  walls  are  uniformly 
thickened  and  on  surface  view  are  polygonal  in  shape.  The  walls 
consist  of  suberin,  a  substance  allied  to  cutin ;  in  some  instances 
they  also  contan  lignocellulose,  forming  cork  stone-cells,  as  in 
asclepias  and  calumba.  The  young  cells  may  contain  a  thin  layer 
of  cytoplasm  and  a  nucleus ;  they  usually  also  contain  brownish 
masses  of  tannin  or  tannin-like  compounds,  and  occasionally  crys- 
tals of  cerin  or  calcium  oxalate. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       291 

Cork  not  only  occurs  as  a  secondary  protective  layer,  but  may 
also  arise  in  other  parts  of  the  plant  as  a  result  of  injury,  as  in 
leaves,  fruits,  stems,  and  tubers.  It  also  arises  as  a  result  of  the 
disarticulation  of  the  leaf  in  autumn. 

PERIDERM. — The  epidermis  is  not  adapted  for  the  protection 
of  the  perennial  plant  organs  on  account  of  its  thin,  frequently 
delicate  structure  and  its  inability  to  continue  with  the  increase  in 
thickness  of  stems  and  roots.  Hence  it  becomes  replaced  by  the 
periderm,  which  consists  of  a  lasting  tissue,  the  CORK,  and  of  a 
meristematic  tissue,  the  PHELLOGEN,  which  reproduces  the  cork 
when  it  becomes  torn  or  destroyed,  by  the  continued  growth  in 


FIG.  156.  Section  through  a  secondary  lenticel  in  the  bark  of  Sassafras;  e,  epidermis:, 
st,  stone  cells;  phel,  phelloderm  derived  from  secondary  phellogen  and  having  thick  ligni- 
fied  wall;  p,  parenchyma;  c,  cork;  com,  complementary  cells. — After  Weiss. 

thickness  of  stems  or  roots.  Cork  is  not  only  of  sub-epidermal 
origin,  but  may  occur  deeper  in  the  cortex  (Fig.  158),  or  even  in- 
side the  endodermis.  In  the  latter  case,  as  in  roots,  it  owes  its; 
existence  to  the  activity  of  the  pericambium.  Superficial,  i.e.,. 
hypodermal  cork,  is  extremely  rare  in  roots.  Not  infrequently  a 
layer  of  cells  is  formed  inside  of  the  phellogen,  being  termed  the 
phelloderm.  They  usually  contain  plastids ;  the  walls  are  moder- 
ately thick  and  free  from  intercellular  spaces  (Fig.  156). 

Lenticels  may  be  described  as  biconvex  fissures  in  the  periderm 
which  permit  of  the  easy  access  of  air  to  the  intercellular  spaces 
of  the  rather  loosely  arranged  cells  lying  beneath  them  (Fig. 


292  A  TEXT-BOOK  OF  BOTANY. 

156).  They  usually  arise  as  the  product  of  a  meristem  situated 
beneath  the  stomata  of  the  epidermis,  the  stomata  being  replaced 
by  them  when  cork  is  developed.  Several  types  of  lenticels  are 


FIG.  157.     Bark  of   Rhamnus  Purshiana  showing  large  whitish  patches  of   lichens, 
and  numerous  lens-shaped  lenticels, 

distinguished.  They  are  quite  characteristic  and  prominent  in 
a  number  of  barks,  as  those  of  species  of  Betula,  Prunus,  Rham- 
nus (Fig.  157),  etc. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       293 


FIG.  158.  Development  of  Cork:  A,  in  epidermal  cells  of  stem  of  Oleander;  B, 
development  of  cork  in  upper  row  of  collenchymatous  cells  in  the  stem  of  Sambucus  nigra; 
C,  development  of  cork  meristem  in  cells  of  cortex  immediately  above  the  primary  bast 
fibers  in  Rubus  fruticosus;  D,  development  of  primary  cork  in  cells  above  the  secondary 
bast  fibers  of  Clematis  Vitalba;  e,  epidermal  cells;  k,  cork;  km,  cork-meristem ;  c,  collen- 
chyma;  b,  parenchyma;  b,  b,  primary  bast  fibers;  b',  secondary  bast  fibers;  K,  young 
cork  cells, — After  Dippel  in  "Das  Mikroskop." 

BORK. — The  cork  cambium  or  phellogen  develops  before  ma- 
turity in  the  green  stems  of  woody  plants  belonging  to  the  dico- 
tyledons. It  may  develop  in  the  primary  or  secondary  tissues 


294 


A  TEXT-BOOK  OF  BOTANY. 


(Fig.  158).  When  the  phellogen  develops  in  the  deep-seated 
tissues,  the  cells  outside  of  the  corky  layer  sooner  or  later  die  and 
slough  off.  This  is  due  to  the  fact  that  the  cork  cells  are  suberized 
and  do  not  permit  the  passage  of  the  cell-sap  containing  food  sub- 
stances. In  large  shrubs  and  trees  with  thick  stems  and  trunks 


FIG.  159.  Development  of  Bork:  A,  in  bark  of  cherry  (Prunus  Cerasus),  showing 
a  layer  of  periderm  (k)  with  thin-walled  cork  cells;  bast  fibers  (Bf);  parenchyma  (p); 
stone  cells  (st)  occasionally  branching  and  lengthened  into  fibers.  B,  inner  layer  of  periderm 
of  Quercus  Robur,  showing  compactly  arranged,  thick-walled  cork  cells  (P)  filled  with  a 
reddish  phlobaphene  or  altered  tannin;  starch-bearing  parenchyma  (p);  stone  cells  (st); 
sieve  tubes  (Bg) ;  bast  fibers  (Bf) ;  prism  of  calcium  oxalate  (kr) ;  several  rows  of  thick- 
walled,  porous  cells  (x). — After  Dippel  in  "Das  Mikroskop." 

a  number  of  successive  layers  of  cork  or  periderm  are  formed. 
These  layers  with  the  dead  cortical  tissues  between  them  persist 
to  some  extent  and  constitute  what  is  known  as  bork,  i.e.,  bork 
consists  of  a  number  of  alternate  layers  of  periderm  and  cortical 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       295 

tissues.  The  cork  cells  in  different  trees  are  variously  developed 
and  accordingly  two  types  of  bork  formation  may  be  distinguished. 
In  sycamore,  cherry  and  plum  trees  the  cork  cells  are  only  slightly 
thickened  (Fig.  159)  and  the  periderm  in  the  form  of  layers 


FIG.  160.      White  oak  bark  with  the  fissured  corky  layers  (bork). 

separates  from  the  tree  annually.  In  the  oaks,  chestnuts  and 
tulip  poplar  the  cork  cells  (Fig.  159)  are  thick  walled  and  com- 
pactly arranged  so  that,  under  the  stress  of  growth  and  thickness 
of  the  bark,  the  layers  of  periderm  are  split  longitudinally,  giving 


296  A  TEXT-BOOK  OF  BOTANY. 

rise  to  the  deep  furrows  (Fig.  160)  which  are  so  characteristic 
of  the  outer  surface  of  our  large  trees. 

Laticiferous  or  milk  tissue  occurs  in  all  those  plants  which 
emit  a  milk- juice  on  being  cut  or  otherwise  wounded.  The  juice 
may  be  colorless,  as  in  the  oleander;  whitish,  as  in  the  Asclepia- 
daceae,  Apocynaceae,  etc. ;  or  yellowish,  as  in  the  Papaveracese. 
It  contains  caoutchouc,  oils,  resins,  mucilage,  starch,  calcium 
oxalate  and  alkaloids  as  well.  The  walls  are  relatively  thin  and 
consist  chiefly  of  cellulose.  The  tissue  consists  either  of  single 
cells  of  definite  length,  as  in  the  Papaveracese,  or  the  cells  may  be 
of  indefinite  length,  as  in  the  Asclepiadacese,  or  it  may  consist  of 
a  more  or  less  branching  network  (Fig.  127)  formed  by  the 
anastomosing  of  a  number  of  cells,  as  in  Taraxacum  (consult 
paragraph  on  Latex,  pp.  238-241). 

As  has  already  been  stated,  the  latex  of  plants  contains  a  num- 
ber of  plastic  or  trophic  substances, — i.e.,  those  which,  either  at 
once  or  after  being  stored  for  a  time  as  reserve  food,  are  drawn 
into  metabolism  and  serve  as  nutrient  material.  They  also  con- 
tain a  number  of  aplastic  or  non-trophic  substances,  as  caoutchouc, 
resin,  alkaloids,  volatile  oils  and  tannin,  which  are  in  the  nature 
of  metabolic  by-products  and  are  incapable  of  further  metabolism. 
While  it  is  highly  probable  that  the  laticiferous  tissue,  on  account 
of  its  being  always  associated  with  the  phloem,  functions  to  some 
extent  for  the  transportation  o>f  plastic  substances,  yet  it  serves 
another  purpose,  viz.,  to  protect  the  underlying  cells  after  injury 
of  the  plant  by  insects  or'herbivorous  animals.  This  protection 
results  from  the  rapid  coagulation  of  the  exuding  latex  upon 
exposure  to  the  air  and  forming  a  varnish-like  surface.  In  some 
cases  the  latex  contains  a  poisonous  principle  which  exercises  a 
protective  function.  In  Rhus  Toxicodendron  the  principle  causing 
the  eczema,  namely  toxicodendrol,  is  supposed  to  be  formed  in 
laticiferous  tissues  being  transferred  to  the  hairs,  which  upon 
being  broken  liberate  the  poison. 


CELL-CONTENTS  AND  FORMS  OF  CELLS.       297 


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CHAPTER  III 

THE  OUTER  AND  INNER  MORPHOLOGY  OF 
HIGHER  PLANTS. 

INTRODUCTORY. 

IT  may  be  well  to  repeat  at  this  point  that  on  germination  of 
the  megaspore  the  female  gametophyte  bearing  the  egg-cell  is 
formed,  and  that  on  germination  of  a  microspore  the  male  gameto- 
phyte bearing  male  nuclei  is  organized.  The  union  of  egg-cell 
and  a  male  nucleus  gives  rise  to  the  sporophyte  embryo  contained 
in  the  seed,  which  develops  into  the  plant  we  see,  namely,  the 
sporophyte.  The  female  gametophyte  always  remains  concealed 
within  the  embryo-sac,  and  the  male  gametophyte  may  be  said  to 
embody  the  protoplasmic  contents  of  the  pollen  tube. 

A  complete  flower  is  made  up  of  floral  leaves  and  sporophylls, 
the  latter  being  essential  for  the  reason  that  they  give  rise  to  the 
spores.  While  the  flower  belongs  to  the  sporophyte  generation, 
the  propagative  organs  may  be  said  to  be  derived  from  both  the 
sporophyte  and  gametophyte,  and  hence  may  be  distinguished  as 
asexual  and  sexual.  The  following  outline  illustrates  their 
derivation : 


Propagative 
Organs 


Sexual,  derived  from 
gametophytes  (sex- 
ual generation) 


Egg-apparatus, 

containing    egg-cell 
female  gamete 


or 


Asexual,  derived  from 
sporophyte  (asex- 
ual generation) 


298 


Male  Generative-cell, 
giving     rise     to     male 
nuclei  or  male  gametes 

Microsporangium  (pollen 
sacs)  giving  rise  to 
microspores  (pollen 
grains) 

Megasporangium  (nucel- 
lus)  giving  rise  to  mega- 
spore  (embryo- sac) 


MORPHOLOGY  OF  HIGHER  PLANTS. 


299 


The  vegetative  organs  comprise  the  root  and  shoot,  the  latter 
being  usually  differentiated  into  shoot  axis  or  stem,  and  leaves. 
The  usual  type  of  shoot  is  one  which  bears  leaves  and  is  exposed 
to  the  light.  The  work  of  carbon  dioxide  assimilation  (photosyn- 
thesis) being  carried  on  for  the  most  part  by  the  leaves,  the  axis 
is  sometimes  spoken  of  as  the  "  assimilation  shoot." 


FIG.  161.  A,  advanced  stage  of  germination  of  the  common  garden  pea  (Pis-urn  sa- 
tivum)  showing  growing  point  of  root  protected  by  root-cap  (p);  root  branches  or  second- 
ary roots  (rb) ;  hypocotyl  (he) ;  epicotyl  or  stem  above  the  cotyledons  (ec) ;  cotyledons 
(one  in  view)  (c).  B,  plantlet  of  white  or  yellow  mustard  (binapis  alba)  show;ng  copious 
development  of  root- hairs  (h). 

I.  OUTER  MORPHOLOGY  OF  THE  ROOT. 

THE  ROOT,  or  descending  axis  of  the  plant,  normally  pene- 
trates the  soil,  absorbing  inorganic  substances  in  solution  and  act- 
ing as  an  anchor  and  support  for  the  shoot.  True  roots  are  found 
only  among  plants  having  a  vascular  system,  as  the  Spermophytes 
and  the  higher  Pteridophytes,  although,  on  the  other  hand,  some 
of  the  higher  plants  do  not  possess  them,  as  certain  of  the  sapro- 
phytic  orchids  and  some  of  the  aquatic  plants  as  Utricularia, 


300 


A  TEXT-BOOK  OF  BOTANY. 


Lemna,  etc.  If  we  take  a  germinating  plant  and  mark  the  root 
into  ten  equal  divisions,  beginning  at  the  apex,  and  place  the 
plant  in  a  moist  chamber,  it  will  be  found  in  the  course  of  one 
or  two  days  that  the  marks  between  I  and  5  have  become  much 


FIG.  162.      Longitudinal  section  through  the  tip  of  the  root  of  Indian  corn  (Zea  Mays) 
showing  root-cap:  a,  outer  layer;  i,  inner  layer. — After  Sachs. 

farther  apart,  and  that  the  growth  in  this  region  is  about  three 
times  that  between  5  and  10.  This  experiment  indicates  that  the 
growth  of  the  root  takes  place  at  or  near  the  apex,  this  region 
being  known  as  the  point  of  growth,  or  point  of  vegetation  (Fig. 
162). 


MORPHOLOGY  OF  HIGHER  PLANTS.     301 

Upon  examining  the  tip  of  a  very  young  root  by  means  of  the 
microscope,  it  will  be  seen  that  the  growing  point  is  protected  by 
a  cup-shaped  body  of  a  more  or  less  solid  structure  and  frequently 
mucilaginous;  this  is  known  as  a  ROOT-CAP.  Its  function  is  to 
protect  the  growing  point,  and  it  exists  in  all  roots  of  terrestrial, 
epiphytic,  and  aquatic  plants  except  the  parasites. 

Just  above  the  root-cap  there  is  developed  a  narrow  zone  of 
delicate  hairs,  which  arise  from  the  surface  cells  and  are  usually 
thin-walled  and  unicellular.  These  are  known  as  ROOT-HAIRS 
(Fig.  161,  B)  and  their  function  is  twofold:  (i)  They  secrete  an 
acid  which  renders  the  inorganic  substances  of  the  earth  soluble, 
and  (2)  they  absorb  these  and  other  substances  for  the  nourish- 
ment of  the  plant.  It  should  be  stated  that  there  are  a  number  of 
plants  which  for  various  reasons  do  not  possess  root-hairs,  such 
as  water-plants,  marsh-plants,  certain  Coniferae,  Ericaceae,  etc. 

When  the  primary  root  persists  (as  in  Gymnosperms  and 
Dicotyledons)  it  increases  considerably  in  length  and  becomes 
ramified ;  if,  at  the  same  time,  it  increases  in  thickness,  and  much 
more  so  than  its  branches,  then  it  is  called  a  TAP-ROOT  (as  in 
Dancus  Beta,  etc.). 

In  the  vascular  cryptogams  (Pteridophytes)  and  the  monocoty- 
ledons the  primary  root  is  generally  thin  and  weak,  frequently 
but  little  ramified,  and  disappears  at  an  early  stage,  being  re- 
placed by  SECONDARY  ROOTS,  as  in  Zea.  Secondary  roots  may 
arise  not  only  upon  the  stem  but  even  upon  leaves,  as  in  Begonia 
and  Bryophyllum.  The  term  LATERAL  ROOTS  is  restricted  to  those 
that  develop  from  the  root  alone. 

The  development  of  roots  upon  shoots  or  of  so-called  "  AD- 
VENTITIOUS ROOTS  "  occurs  in  nearly  all  of  the  woody  plants  of 
the  Spermophyta.  Many  annual  herbaceous  plants  do  not  possess 
this  capacity  at  all.  The  adventitious  roots  arise  from  "  root- 
primordia  "  which  are  formed  under  the  cortex  of  the  shoots. 
While  ordinarily  they  do  not  develop  upon  the  shoots,  yet  if 
cuttings  are  made,  as  of  Coleus,  Geranium,  Rosa,  etc.,  we  find 
"  either  singly  or  on  both  sides  of  the  axillary  buds  "  the  develop- 
ment of  adventitious  roots  from  the  latent  root-primordia. 

Influence  of  Gravity. — The  root  is  popularly  supposed  to 
grow  downward,  in  order  to  avoid  the  light.  On  the  other  hand. 


302 


A  TEXT-BOOK  OF  BOTANY. 


the  theory  has  been  established  (as  a  result  of  Knight's  experi- 
ments) that  the  root. grows  downward  by  reason  of  the  influence 
of  gravity.  In  addition  it  may  be  said  that  the  principal  functions 
of  the  root,  namely,  those  of  absorbing  inorganic  food  materials 
and  of  fixing  the  plant  to  the  soil,  determine  in  a  measure  the 
direction  of  its  growth.  The  tendency  of  the  root  to  grow  down- 
ward is  a  characteristic  which  distinguishes  it  from  other  parts 
of  the  plant,  and  it  is  said  to  be  POSITIVELY  GEOTROPIC  (Fig.  163, 
A). 


FIG.  163.  A,  seedling  of  Brassica  nigra  in  which  root  and  stem  have  curved  into  a 
vertical  position  after  being  laid  horizontally.  B,  seedling  of  Sinapis  alba,  the  hypocotyl 
showing  a  positive,  the  root  in  water  a  negative  heliotropic  curvature.  The  arrows  show 
the  direction  of  the  incident  rays  of  light. — After  Pfeffer. 

The  influence  which  gravity  has  on  plants  may  be  best  under- 
stood by  bearing  in  mind  that  gravity  is  a  constant  force  which 
acts  perpendicularly  to  the  surface  of  the  earth,  and  that  all  parts 
of  the  plant  are  subject  to  its  influence.  The  organs  of  plants 
respond  in  different  ways  to  the  action  of  gravity,  but  a  clear 
distinction  should  be  made  between  mere  mass  attraction,  or  that 
manifestation  of  the  force  of  gravity  whereby  the  heavily  laden 
branch  of  a  fruit  tree  bends  downward,  and  the  stimulus  which 
causes  the  primary  root  of  a  plant  to  grow  downward  and  the 
shoot  to  grow  upward.  While  all  parts  of  the  plant  are  subject 
to  the  influence  of  gravity,  not  all  the  organs  of  plants  respond 
in  an  equal  degree.  This  is  well  illustrated  by  roots  themselves. 


MORPHOLOGY  OF  HIGHER  PLANTS.  303 

It  is  well  known  that,  whatever  the  position  of  the  seed  at  the 
time  of  germination,  the  young  radicle  begins  to  grow  perpen- 
dicularly downward  ( Fig.  163,  A  ) .  The  branches,  however,  which 
arise  on  the  primary  root  are  less  positively  geotropic  and,  instead 
of  growing  downward  parallel  with  the  primary  or  tap  root,  di- 
verge at  an  angle  from  it  (Fig.  161 ) .  The  secondary  branches  are 
still  less  affected  by  gravity  and  diverge  still  more  from  the  per- 
pendicular, or  grow  out  horizontally,  while  still  others  do  not 


FIG.  164.     Over-turned  tree  trunk  showing  spreading  root-system,  the  main  or 
tap  root  having  died  away 

appear  to  be  in  the  least  affected  by  gravity  and  grow  freely  in  any 
direction.  In  the  case  of  large  trees  we  frequently  find  that  the 
lateral  roots  spread  out  in  a  more  or  less  horizontal  plane  near  the 
surface  of  the  earth,  and  if  the  main  root  has  died  the  influence  of 
gravity  is  not  very  evident  (Fig.  164).  But  here  it  must  be  re- 
membered that  gravity  was  instrumental  in  determining  the  direc- 
tion of  growth  at  an  earlier  stage.  This  spreading  of  the  roots 
near  the  surface  of  the  earth  is  of  decided  advantage  to  plants,  for 
it  enables  them  to  avail  themselves  of  the  better  soil  of  the  surface 


304 


A  TEXT-BOOK  OF  BOTANY. 


layers.  As  indicated,  gravity  also  determines  the  upward  perpen- 
dicular direction  of  the  shoot,  which  is  therefore  said  to  be 
NEGATIVELY  GEOTROPic,  but,  as  in  the  case  of  the  root,  the  branches 
are  less  influenced  by  it  and  hence  diverge  at  various  angles  from 
the  main  axis. 

Some  of  the  other  effects  of  gravity  may  be  noted.    If  the  end 
of  a  shoot  be  cut  off,  the  branches  next  to  the  top  will  grow  per- 


FIG.  165.  Mangr6*ve  forest  (Rhizophora  Mangle),  showing  the  habit  of  growth,  es- 
pecially the  numerous  aerial  roots  which  form  an  almost  impenetrable  thicket.  The  man- 
grove is  common  along  the  southern  shores  of  Florida,  in  the  Bahama  Islands,  and  in  the 
West  Indies.  Many  shellfish,  lobsters,  and  other  forms  of  sea  life  are  often  found  clinging 
or  attached  far  up  on  the  roots  where  they  become  lodged  during  high  tides. — Photograph 
from  article  by  Henry  Trimble  on  Mangrove  Tannin  in  Contributions  from  the  Botanical 
Laboratory  of  the  University  of  Pennsylvania,  1892,  p.  50. 

pendicularly  upward  and  thus  assume  the  work  of  the  main  axis. 
Likewise  in  the  case  of  roots,  if  the  apex  of  the  main  or  tap  root 
be  cut  off,  the  branches  near  the  end  will  assume  a  perpendicular 
direction.  It  will  frequently  be  noticed  in  the  case  of  trees  which 
have  been  uprooted  or  where  branches  have  been  bent  over  hori- 
zontally that  the  new  branches  which  arise  grow  perpendicularly 
upward.  Creeping  shoots  furnish  another  good  example  showing 


MORPHOLOGY  OF  HIGHER  PLANTS. 


305 


FIG.  166.  Tuberous  root  of  Ginseng  (Panax  quinquefolium) .  The  root  on  the  left  is  a 
fresh  specimen  and  was  grown  in  the  United  States.  The  one  to  the  right  was  purchased  at 
a  Chinese  bazaar.  It  is  translucent,  of  a  yellowish-brown  color,  and  has  the  characteristic 
shape  and  markings  considered  desirable  by  the  Chinese.  The  markings  on  the  upper 
segment  of  the  specimen  are  stem  scars  which  are  usually  found  on  old  roots.  The  trans- 
lucent appearance  is  no  doubt  due  to  the  manner  of  treatment.  While  the  method  is  not 
generally  known,  similar  specimens  may  be  prepared  by  treating  the  recently  gathered 
roots  with  freshly  slaked  lime. 

the  influence  of  gravity,  the  branches  growing  upward  and  the 
roots  downward. 

The  root  exerts  a  certain  amount  of  upward  pressure  on  the 
liquids  in  the  stem.    This  fact  can  be  demonstrated  by  cutting  off 
20 


306  A  TEXT-BOOK  OF  BOTANY. 

the  stem  just  above  the  surface  of  the  earth  and  attaching  thereto 
a  glass  tube  by  means  of  a  tightly-fitting  rubber  tube.  It  is  de- 
sirable to  perform  this  part  of  the  operation  under  water  and  to 
have  the  glass  tube  partly  filled  with  water  at  the  beginning  of 
the  experiment.  This  is  done  to  prevent  the  clogging  up  of  the 
vessels  with  air,  which  prevents  the  ready  passage  of  fluids 
through  them.  If  the  root  is  now  kept  moist,  the  osmotic  pressure 
of  its  cells  forces  water  up  into  the  glass  tube,  sometimes  to  a 
height  of  several  feet.  Experiments  on  the  begonia  and  on  many 
other  plants  succeed  very  well,  but  for  some  reason  the  geranium 
is  impracticable  to  work  with.  The  manometer  devised  by  Ganong, 
while  not  showing  the  quantity  of  water  forced  up  by  the  root, 
shows  the  amount  of  pressure  exerted,  which  is  really  the  most 
important  fact  to  be  ascertained. 

Modified  Roots. — Roots  which  arise  from  the  nodes  of  the 
stem  or  other  parts  of  the  plant  are  known  as  secondary  or  adventi- 
tious roots.  These  include  the  aerial  roots  of  the  banyan  tree 
and  the  Mangrove  (Fig.  165),  which  are  for  the  purpose  of  sup- 
port ;  the  roots  of  the  ivy,  which  are  both  for  support  and  climb- 
ing, and  the  roots  of  Indian  corn  and  many  palms  which  serve  both 
for  support  and  the  absorption  of  nourishment.  Under  this  head 
may  also  be  included  the  aerial  roots  of  orchids  and  the  root-like 
structures,  or  haustoria,  of  parasites,  as  of  mistletoe  and  dodder, 
which  penetrate  the  tissues  of  their  host  plants  and  whose  vascular 
strands  come  into  most  intimate  relations  with  those  of  hosts. 

Of  special  interest  also  are  the  breathing  roots  of  certain 
marsh-plants  which  serve  to  convey  oxygen  to  the  submerged 
parts ;  and  the  assimilation  roots  of  certain  water-plants  and 
epiphytes,  which  are  unique  in  that  they  produce  chlorophyll. 
In  certain  plants  the  roots  give  rise  to  adventitious  shoots,  as  in 
Prunus,  Rubus,  Ailanthus,  etc.,  and  in  this  way  these  plants  some- 
times form  small  groves. 

Root  Tubercles. — The  roots  of  the  plants  belonging  to  the 
Leguminosse  are  characterized  by  the  production  of  tubercles, 
nodules  or  swellings  (Fig.  167)  which  have  been  shown  to  have 
a  direct  relation  to  the  assimilation  of  nitrogen  by  the  plants  of 
this  family.  Like  carbon,  nitrogen  is  one  of  the  elements  essential 
to  plant-life,  being  one  of  the  constituents  of  protoplasm  and 


MORPHOLOGY  OF  HIGHER  PLANTS. 


307 


present  in  various  nitrogenous  (protein)  compounds  which  occur 
as  normal  constituents  of  the  plant.  The  nitrogen  required  by 
plants  is  derived  either  from  nitrogen  salts  contained  in  the  soil, 
as  nitrates  and  ammonium  salts,  or  from  the  free  nitrogen  of 
the  atmosphere.  While  most  of  the  higher  plants  are  able  to 
assimilate  nitrogen  compounds  existing  in  the  soil,  only  the 
Leguminosse  and  Aristolochiaceae,  with  possibly  a  few  exceptions, 
are  able  to  assimilate  atmospheric  nitrogen,  and  in  this  respect  the 


FIG.  167.  Root  tubercles  on  Lupinus,  one  of  the  Leguminosoe:  A,  roots  with  tubercles; 
B,  transverse  section  of  root  showing  the  cells  (b)  which  contain  the  nitrogen  bacteria. — 
A.  after  Taubert;  B,  after  Frank. 

majority  of  the  Leguminosae  stand  as  a  class  by  themselves. 
Apparently  in  direct  relation  to  this  character  stands  the  fact  that 
the  seeds  of  these  plants  contain  a  high  percentage  of  nitrogen. 
This  special  ability  of  the  Leguminosae  to  fix  atmospheric  nitrogen 
in  the  plants  depends  upon  the  presence  of  the  nodules,  which  are 
due  to  the  infection  of  the  roots  by  a  soil-bacterium  (Pseudomonas 
radicicola) ,  although  the  precise  mode  of  fixing  the  nitrogen  is 


3o8  A  TEXT-BOOK  OF  BOTANY. 

not  known.    The  bacteria  seem  to  be  localized  in  the  nodules  and 
are  not  found  in  any  other  part  of  the  plant. 

It  has  been  shown  that  when  the  roots  of  leguminous  plants 
are  free  from  nodules  they  do  not  have  the  power  of  assimilating 
free  nitrogen.  On  the  other  hand,  when  the  nodules  produced  by 
the  bacteria  are  developed,  the  plants  will  grow  in  soil  practically 
free  from  nitrogen  salts.  Because  of  this  power  the  plants  of  this 
family  are  useful  in  restoring  worn-out  land,  i.e.,  land  in  which 


FIG.  168.  Transverse  section  of  a  root  bearing  root  hairs;  the  latter  are  thin  walled, 
irregularly  bent,  and  attached  at  various  places  to  small  particles  of  soil.  The  hairs  secrete 
an  acid,  rendering  the  inorganic  substances  soluble,  which  are  then  diffused  through  the 
walls  of  the  hairs,  transmitted  to  the  cortical  parenchyma  and  distributed  through  the 
conducting  cells  of  the  xylem  to  the  shoot. — After  Frank. 

the  supply  of  nitrogen  is  exhausted,  and  they  thus  play  an  impor- 
tant role  in  agricultural  pursuits. 

The  enriching  of  the  soil  is  accomplished  by  ploughing  under 
the  leguminous  crops,  as  of  clover  or  alfalfa,  or  allowing  the 
nodule-producing  roots  to  decay,  when  the  nitrogen  compounds 
are  distributed  in  the  soil. 

(Consult  Bulletins  on  "  Soil  Inoculation  for  Legumes,"  issued 
by  the  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agri- 
culture.) 


MORPHOLOGY  OF  HIGHER  PLANTS.  309 

THE  INNER  STRUCTURE  OF  THE  ROOT. 

Primary  Structure. — If  we  make  a  transverse  section  of  the 
young  portion  of  a  root  (Vascular  Cryptogam,  Gymnosperm,  or 
Phenogam),  we  notice  the  following  tissues  (Figs.  169-174). 
The  outermost  tissue  is  EPIDERMIS  (E),  it  being  generally  thin- 
walled  and  destitute  of  cuticle ;  it  is,  as  a  rule,  hairy,  and  these 
hairs,  which  are  relatively  long,  but  always  unicellular,  are  known 
as  ROOT-HAIRS  (Figs.  161,  1 68)  ;  they  ramify  but  very  seldom. 
Inside  the  epidermis  there  is  frequently  present  a  HYPODERMIS 


FIG.  169.  Radial  vascular  bundle  in  root  of  Allium  ascalonicum,  showing  a  large 
central  trachea  from  which  radiate  five  small  groups  of  tracheae  and  between  which  are  the 
groups  of  leptome  or  sieve;  p,  layer  of  pericambium  or  pericycle;  d,  transition  cells  or  pas- 
sage cells  in  the  endodermal  layer,  and  which  permit  the  easy  transfer  of  substances  between 
the  cortical  parenchyma  and  the  tracheae  of  the  stele. — After  Haberlandt. 

(sometimes  referred  to  as  an  EXODERMIS)  composed  of  a  single 
layer  of  cells  or,  at  the  most,  of  but  several  layers,  the  cells  of 
which  differ  in  shape  and  size  from  those  of  the  epidermis  and  the 
adjoining  cortical  parenchyma.  The  hypodermis  takes  the  place  of 
the  epidermis  when  the  latter  is  worn  off,  except  in  the  few  cases 
where  hypodermal  cork  becomes  developed,  as  in  Cephalanthus, 
Solidago,  and  in  the  Bignoniaceae. 

The  root  bark  is  composed  of  parenchymatous  cells,  being 


3io  A  TEXT-BOOK  OF  BOTANY. 

commonly  referred  to  as  the  CORTEX,  and  is  either  homogeneous 
or  divided  into  two  zones,  the  outer  or  peripheral  being  composed 
of  thick-walled  cells  which  naturally  belong  to  the  hypodermis 
and  an  inner  or  internal  strata  made  up  of  thin-walled  cells.  The 
cells  of  the  cortical  parenchyma  may  contain  starch,  calcium 
.oxalate,  calcium  carbonate,  and  there  may  be  associated  with  them 


FIG.  170.  Cross-section  of  the  primary  root  of  a  germinating  plant  of  Phaseolus 
multiflorus,  showing  development  of*  secondary  structures:  p,  group  of  primary  vessels; 
g,  larger  tracheae  of  secondary  development  formed  between  the  four  primary  strands  of 
xylem;  b,  the  four  groups  of  phloem  alternating  with  the  four  initial  groups  of  xylem  and 
beneath  which  secondary  tracheae  are  forming  (g');  pc,  pericambium  (pericycle),  a  layer  of 
cells  beneath  the  endodermis  (s).  A  few  layers  of  cortical  parenchyma  are  shown  outside 
of  the  endodermis.  In  the  middle  is  a  well-developed  pith  (M)  which  sometimes  is  developed 
in  roots. — After  Sachs. 

secretory  cells  or  receptacles.  Immediately  beneath  the  innermost 
layer  of  cortical  parenchyma  is  a  distinct  layer  of  cells  usually 
considered  part  of  the  cortex  and  known  as  the  ENDODERMIS.  It 
consists  always  of  a  single  layer  of  cells,  without  any  intercellular 
spaces,  and  the  radial  walls  show  in  transverse  section  Casparyan 
spots,1  depending  upon  a  local  folding  of  the  cell- wall,  which  is 
here  suberized.  In  the  course  of  time  the  cell-walls  of  the  en- 

1 "  Physiologische  Pflanzenanatomie,"  by  Dr.  G.  Haberlandt,  p.  245. 


MORPHOLOGY  OF  HIGHER  PLANTS.     311 

dodermis  frequently  become  thickened,  either  all  around,  or  only 
on  the  inner  or  radial  walls,  so  that  we  might  speak  of  an  O- 
endodermis  as  in  Honduras  sarsaparilla  or  an  U-endodermis  as 
in  Mexican  sarsaparilla,  according  to  the  manner  of  thickening. 


FIG.  171.  Cimicifuga.  Transverse  section  of  the  central  part  of  a  mature  root  in 
which  the  secondary  changes  are  completed:  a,  parenchyma  of  primary  cortex;  b,  endo- 
dermis;  c,  cambium  zone;  d,  tracheae  in  secondary  xylem;  e,  broad,  wedge-shaped  medullary 
ray;  f,  outer  portion  of  one  of  the  primary  xylem  bundles;  g,  pericycle-parenchyma  beneath 
the  endodermis;  h,  inter-fascicular  cambium. — After  Bastin. 

This  is  especially  the  case  in  the  monocotyledons  where  the  walls 
of  the  endodermal  cells  become  completely  suberized  and  im- 
permeable to  water.  In  some  roots  the  cells  of  the  endodermis 
may  be  uniformly  thick-walled  throughout,  while  in  others  some 


3i2  A  TEXT-BOOK  OF  BOTANY. 

of  the  cells- may  remain  thin-walled,  and  these  cells,  the  so-called 
"  transition  cells  "  or  "  passage  cells,"  form  channels  of  com- 
munication between  the  cortical  parenchyma  and  the  vessels  of 
the  stele  (Fig.  169)  ;  they  are  therefore  located  just  outside  the 
peripheral  vessels  of  each  ray  of  the  xylem  (or  hadrome). 

Inside  the  endodermis  is  the  STELE,  formerly  called  the  central- 
cylinder.  In  this  the  peripheral  stratum,  sometimes  composed  of 
two  or  three  layers  of  cells,  represents  the  PERICAMBIUM  (or 
PERICYCLE).  The  cells  are  generally  thin-walled,  and  in  Dicotyle- 
dons and  Gymnosperms  are  able  by  cell-division  to  form  cork  and 


RB 


FIG.  172.  A  transverse  section  through  the  root  of  a  germinating  pea-plant  (Pisum) 
about  40  mm. from  the  tip, showing  the  origin  of  a  root-branch  (RB);  E,  epidermis;  C,  pri- 
mary cortex;  X,  hadrome  (vessels);  P,  leptome  (sieve);  EN,  endodermis. 

secondary  cortex,  but  in  all  vascular  plants  it  is  capable  of  giving 
rise  to  "lateral  branches"  or  "lateral  roots"  (Figs.  161,  172), 
hence  it  is  frequently  referred  to  as  the  "  RHIZOGENOUS  LAYER/' 

Inside  the  pericambium  (by  some  authors  compared  with  the 
pericycle  of  the  stem)  we  find  strands  of  phloem  (or  leptome) 
(P)  alternating  radially  with  a  corresponding  number  of  strands 
of  xylem  (or  hadrome)  (X).  The  number  of  these  strands  vary 
in  the  different  groups  of  plants  (Figs.  169-174),  being  highest  in 
the  monocotyledons  where  a  pith  is  developed,  as  in  sarsaparilla, 
several  grasses,  palms,  etc.  This  peculiar  arrangement  of  the 


MORPHOLOGY  OF  HIGHER  PLANTS.  313 

phloem  and  xylem,  as  separate  strands  alternating  with  each  other 
and  not  being  located,  as  in  stems,  in  the  same  radii,  has  given 
rise  to  several  adverse  views.  Some  authors  have  considered 
the  root-stele  as  one  single  mestome-strand  (or  fib ro vascular 
strand),  while  others,  especially  of  recent  date,  consider  it  to  be 
composed  of  several  MESTOME  STRANDS. 

The  xylem  or  hadrome  contains  tracheae  or  vessels,  the  periph- 
eral being  spiral  and  narrower  than  the  inner,  which  are  scalari- 
form  or  reticulate.  The  tissue  in  the  center  of  the  stele  in  mono- 
cotyledons is  not  uncommonly  made  up  of  parenchyma  cells,  and 


FIG.  173.  Primary  structure  in  the  root.  Transverse  section  of  root  of  pea  (Pisum) 
about  40  mm.  from  the  root-cap:  H,  epidermal  cells,  some  of  which  are  developed  into 
root-hairs;  C,  primary  cortex;  EN,  endodermis;  PC,  pericambium;  X,  hadrome,  composed 
of  tracheae;  P,  leptome,  composed  of  sieve  cells,  the  hadrome  (vessels)  and  leptome  (sieve) 
forming  a  triarch  radial  fibrovascular  bundle. 

corresponds  exactly  with  the  pith  of  the  stem.  In  roots  it  is  often 
called  CONJUNCTIVE  TISSUE,  and  the  cells  may  contain  starch  and 
crystals  of  calcium  oxalate. 

Secondary  Structure. — In  roots  that  are  able  to  increase  in 
thickness  (as  in  Gymnosperms  and  Dicotyledons),  the  increase 
depends  upon  the  activity  in  the  pericambium,  some  of  the  cells 
becoming  meristematic.  These  meristematic  cells  are  known  as 
phellogen,  developing  cork  outwardly  and  secondary  cortex  in- 
wardly. The  meristem  of  the  stele  or  cambium  also  becomes  very 
active  and  develops  on  the  inner  face  of  the  phloem  and  extends 


A  TEXT-BOOK  OF  BOTANY. 


from  there  to  the  outside  of  the  peripheral  vessels  of  the  xylem 
(Fig.  174)  ;  thus  a  continuous  cambial  zone  gradually  arises. 
From  this  zone  secondary  tracheae  or  vessels  become  developed  on 
the  inner  face  of  the  primary  phloem,  while  secondary  phloem 
becomes  differentiated  outside  the  primary  rays  of  xylem ;  or 
only  parenchyma  develops  outside  the  primary  xylem,  resulting  in 


sx 


FIG.  174.  Section  in  the  older  part,  higher  up  on  the  root  of  pea  (Pisum),  showing  in 
addition  to  what  has  been  observed  in  Fig.  1 73,  the  beginning  of  the  change  from  primary  to 
secondary  structure:  CA,  the  development  of  a  cambium;  SX,  secondary  hadrome  (or 
vessels),  and  SP,  secondary  leptome  (or  sieve). 

the  formation  of  secondary  PARENCHYMA-RAYS  (or  medullary 
rays).  In  other  words,  the  original  radial  structure  of  the  stele 
changes  to  the  collateral  type  (Fig.  175).  Owing  to  this  increase 
within  the  stele,  the  peripheral  tissues  from  the  endodermis  to  the 
epidermis  naturally  become  broken  and  are  subsequently  thrown 
off,  but  are  replaced  by  the  pericambial  cork  and  secondary  cor- 
tex derived  from  the  pericambium.  The  older  roots,  then,  of 
Gymnosperms  and  Dicotyledons  thus  resemble  the  structure  of 
stems,  except  that  no  pith  exists  in  these  roots,  at  least  not  usually. 


MORPHOLOGY  OF  HIGHER  PLANTS.     315 

Some  differences  are,  however,  quite  noticeable  in  some  instances, 
as  in  the  thick  roots  of  Beta,  Radish,  etc.,  where  the  wood  paren- 


M 


FIG.  175.  Fully  developed  secondary  structure  in  root.  Transverse  section  of  root 
of  pea  (Pisurn)  at  the  end  of  the  summer's  growth:  E,  some  epidermal  cells  with  fragments 
of  root-hairs;  C,  primary  cortex;  EN,  endodermis;  K,  pericambial  cork;  B,  bast  fibers; 
SC,  secondary  cortex;  S,  sieve;  T,  tracheae;  W,  wood  fibers;  WP,  wood  parenchyma; 
M,  medullary  rays;  the  tracheae  (or  vessels)  and  leptome  (or  sieve)  forming  open  collateral 
fibrovascular  bundles,  these  being  found  in  dicotyledons  with  but  few  exceptions. 

chyma  is  usually  abundant,  thin-walled,   and  not   lignified,  the 
annual  rings  also  being  mostly  indistinct. 

The  characteristic  distinguishing  the  primary  and  secondary 


A  TEXT-BOOK  OF  BOTANY 


-1? 


FIG.  176.  Glycyrrhiza:  A,  transverse  section;  B,  longitudinal  section.  B,  bark; 
H,  wood;  X,  cambium  zone;  ph,  cork  cells;  rp,  cortex;  p,  parenchyma;  k,  crystal  fibers; 
s,  sclerenchyma  fibers,  including  wood  fibers  occurring  in  the  wood  and  bast  fibers  present 
in  the  bark;  t,  tracheae;  m,  medullary  rays. — After  Meyer. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


317 


structures  of  dicotyledonous  roots  may  be  summarized  as  follows : 

PRIMARY  STRUCTURE:  Epidermis  and  root-hairs.  Hypoder- 
mis.  Primary  cortex  consisting  of  parenchyma.  Endodermis, 
pericambium,  xylem  arranged  in  radial  rays  which  alternate 
with  phloem  or  sieve  strands,  constituting  a  radial  fibrovascular 
bundle  (Figs.  169-174). 

SECONDARY  STRUCTURE:  Cork  cells,  phellogen,  secondary  cor- 
tex consisting  of  parenchyma.  Phloem,  cambium,  and  xylem 
arranged  in  radial  groups,  forming  open  collateral  fibrovascular 
bundles.  Medullary  rays  separating  the  fibrovascular  bundles 
(Figs.  175-177). 

Sometimes,  as  in  glycyrrhiza  and  valerian,  a  number  of  paren- 
chyma cells  are  found  in  the  center  of  the  root,  these  constituting 
the  PITH  (Fig.  176)  or  medulla;  but  they  are  usually  wanting  in 
dicotyledonous  roots. 

Wood  and  bark  are  terms  used  to  distinguish  those  portions 
of  the  root  or  stem  separated  by  the  cambium;  all  that  portion 
inside  of  the  cambium,  including  xylem,  medullary  rays,  and 
pith,  being  known  as  the  WOOD.  The  BARK  includes  the  hadrome, 
the  medullary  rays  outside  of  the  cambium,  and  the  tissues  formed 
by  the  phellogen,  vis.,  secondary  cortical  tissue  and  cork. 

The  following  diagram  of  the  secondary  structure  of  a  dicoty- 
ledonous root  may  be  of  assistance  in  understanding  the  origin 
and  relation  of  the  tissues  comprising  it : 


Wood  made  up  of 


Cambium  produces 


Bark  made  up  of 


f  Pith,  which  may  be  wanting. 

J  f  Composed  of  vessels,  wood  parenchy- 

\  ma  and  wood  fibers ;  or  tracheids  may 
Xylem. .  J  replace  these  cells,  or  be  associated 
*       with  them.      These  are  arranged  in 
groups  forming   radial    rows  which 
are  separated  by  medullary  rays. 


Phloem . . 


Consisting  of  leptome  and  companion 
cells;  bast  fibers  may  also  be  present. 
These  are  arranged  in  collateral 
groups  and  form  radial  rows  which 
are  separated  by  medullary  rays. 


Meristem  of  pericambium  producing  pericambial- 
cork  and  parenchyma.  Phellogen  later  forming 
periderm  in  stems  several  years  old,  and  borlk 
in  the  trunk  of  large  shrubs  and  trees. 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  177.  A,  transverse  section  of  Phytolacca  root,  showing  the  fibrovascular  bundles 
(V,  V,  V",)  which  are  produced  by  distinct  cambiums  (C).  The  parenchyma  contains  little 
starch,  and  some  of  the  cells  (R)  show  short  raphides  of  calcium  oxalate,  many  of  the  crystals 
being  distributed  in  the  section. 

B.  Transverse  section  of  Belladonna  root  which  is  two  or  three  years  old.  There  is  but 
one  cambium  zone  (C) .  Most  of  the  parenchyma  contains  starch  (St) ,  the  remaining  cells 
containing  cryptocrystalline  crystals  of  calcium  oxalate. 

K.  cork;  S,  sieve;  W.  wood  fibers  and  T,  tracheae,  both  of  which  are  strongly  lignified  in 
Belladonna  root;  M.  medullary  rays. 


MORPHOLOGY  OF  HIGHER  PLANTS.  319 

The  root  branches  arise  as  the  result  of  the  development  of 
primary  meristems  in  the  pericambium  (Figs.  161,  172).  The 
tissues  forming  the  branches  are  directly  connected  with  the 
fibrovascular  tissues  of  the  root  and  protrude  through  the  over- 
lying tissues  without  having  any  connection  with  them.  The 
structure  of  the  branches  thus  formed  corresponds  to  the  primary 
structure  of  the  roots,  and  in  the  case  of  dicotyledonous  roots 
may  also  subsequently  develop  a  secondary  structure.  Goebel 
states  that  in  plants  which  grow  in  moist  soil,  or  whose  roots  func- 
tion only  for  a  short  time,  the  branches  may  be  altogether  sup- 
pressed, as  in  Colchicum,  Arissema,  etc. 

Contraction  of  roots  is  observed  in  both  monocotyledons 
and  dicotyledons,  it  being  most  apparent  in  the  former,  as  in  the 
roots  of  Veratrum  viride  (Fig.  178).  The  uneven  or  corkscrew- 
like  appearance  is  due  to  a  contraction,  which  arises  as  follows : 
Some  of  the  longitudinally  elongated  cells  beneath  the  epidermis, 
as  well  as  cells  extending  to  and  including  the  endodermis,  absorb 
large  quantities  of  water,  which  causes  them  to  assume  a  spherical 
form  (as  the  cells  of  a  potato  are  altered  on  boiling),  the  result 
being  a  longitudinal  contraction  of  the  root  at  this  point.  In  this 
way  the  plant  is  fastened  more  securely  to  the  earth,  and  at  the 
end  of  the  season's  growth  the  apical  buds  of  plants,  with  upright 
rhizomes,  as  of  Veratrum  viride,  Dracontium,  etc.,  are  drawn 
into  the  earth  and  thus  protected  during  the  winter  season. 

Abnormal  Structure  of  Roots. — It  is  often  difficult  to  recog- 
nize the  type-structure  of  dicotyledonous  roots  in  drugs,  owing 
to  the  anomalous  and  abnormal  secondary  structure.  Scleren- 
chymatous  fibers,  while  present  in  glycyrrhiza  (Fig.  176)  and 
althaea,  are  not  infrequently  wanting.  Wood  fibers  may  be  spar- 
ingly developed,  as  in  young  belladonna  roots  (Fig.  177),  or  even 
wanting,  as  in  gentian.  In  other  cases  the  medullary  rays  are 
abnormal,  being  replaced  in  calumba  by  wood  parenchyma,  and 
in  ipecac  and  taraxacum  by  sclerenchymatous  cells.  In  asclepias 
and  calumba  a  layer  of  stone  cells  occurs  near  the  periphery ;  in 
gelsemium  sieve  cells  develop  in  the  xylem ;  in  senega  the  xylem  is 
not  uniformly  developed,  and  in  still  other  cases,  as  in  jalap, 
pareira,  and  phytolacca  (Fig.  177,  A),  successive  cambiums  de- 
velop, producing  concentric  series  of  open  collateral  fibrovascular 
bundles. 


320  A  TEXT-BOOK  OF  BOTANY. 

II.    THE  OUTER  MORPHOLOGY  OF  THE  STEM. 

The  stem,  or  ascending  axis  of  the  plant,  usually  grows  in  a 
direction  opposite  to  that  of  the  root,  seeking  the  light  and  air. 
The  tendency  of  the  stem  to  grow  upward  is  characteristic  of 
the  majority  of  plants,  and  is  spoken  of  as  NEGATIVE  GEOTROPISM. 
The  growing  point  of  the  stem  is  at  the  apex,  and  it  is  protected 
by  a  layer  of  bud  scales  (Fig.  179,  B). 


FIG.  178.  Longitudinal  section  through  a  root  of  Veratrum  viride  showing  the  nature 
of  the  contraction  of  the  root:  E,  epidermis;  CS,  cells  of  cortex  containing  starch;  CO, 
cells  of  cortex  containing  raphides;  F,  fibro vascular  bundle;  A,  rifts  or  cavities  formed  as 
a  result  of  the  radial  swelling  of  the  cells  of  the  cortex. 

Stems  are  further  characterized  by  bearing  leaves,  or  modi- 
fications of  them.  The  leaves  occur  at  regular  intervals  in  the 
same  species,  and  that  portion  of  the  stem  from  which  they  arise 
is  spoken  of  as  a  NODE,  while  the  intervening  portion  is  called  an 
internode. 

Stem  branches  usually  arise  in  the  axils  of  the  leaves,  first 


MORPHOLOGY  OF  HIGHER  PLANTS. 


321 


appearing  as  little  protuberances,  sometimes  spoken  of  as  pri- 
mordia,  on  the  stem.  Their  origin  differs  from  that  of  the  root 
branches,  in  that  they  arise  from  meristematic  or  embryonic  tissue 
developed  just  beneath  the  epidermis.  The  branches,  like  the 
main  axis,  manifest  negative  geotropism,  although  to  a  lesser 
degree.  They  likewise  possess  a  growing  point  at  the  apex, 
covered  with  embryonic  leaves  (Fig.  179).  Not  infrequently 
more  than  one  branch  arises  in  the  leaf  axil. 

Buds  may  be  defined  as  undeveloped   shoots   in  which  the 
foliage  is  yet  rudimentary.     The  buds  at  the  ends  of  stems  or 


~P 


FIG.  179.  A,  longitudinal  section  through  the  apical  region  of  the  stem  of  the  embryo 
of  a  bean  (Phaseolus  multiftorus) ;  ss,  apex;  pb,  parts  of  the  two  first  leaves,  and  their 
axillary  buds  (k,  k,);  r,  periblem  or  primary  cortex.  B,  diagram  of  longitudinal  section 
through  winter  bud  of  Quercus  coccinea:  P,  growing  point;  L,  young  leaves;  SB,  stem 
branches;  F,  fibro vascular  bundle. — A,  after  Sachs. 

branches  are  known  as  APICAL,  or  TERMINAL  BUDS,  and  those  situ- 
ated in  the  axils  of  the  leaves,  as  AXILLARY  BUDS.  In  some  cases 
they  are  protected  by  scales,  as  in  hickory,  when  they  are  known  as 
scaly  buds;  while  buds  which  are  not  thus  protected  are  called 
naked  buds.  They  are  further  distinguished  as  leaf,  flower,  and 
mixed  buds,  as  they  develop  into  leaves  or  flowers,  or  both. 

We  have  to  distinguish  between  overground  shoots  and  under- 
ground shoots.  The  former  are  sometimes  designated  as  epi- 
geous  (upon  the  earth)  and  the  latter  as  hypogeous  (under  the 
earth). 


21 


322 


A  TEXT-BOOK  OF  BOTANY. 


Epigeous  Shoots. — As  would  be  supposed,  these  two  kinds 
of  shoots  vary  to  a  certain  extent.  In  epigeous  shoots  a  number 
of  features  may  be  noted.  If  the  internodes  are  long  the  leaves 
do  not  usually  interfere  with  one  another  so  far  as  exposure  to 
light  is  concerned,  but  if  the  internodes  are  short,  the  leaves  are 
all  brought  close  together  on  the  axis,  and  hence,  were  it  not  for 


PIG.   180.     A,  woody  vine  of  Canada  moonseed  (Menispermum  canadense) ,  which  ascends 

by  twining  to  the  right. 
B,  stem  of  wild  yamroot  (Dioscorea  mllosa),  which  ascends  by  twining  to  the  left 

and  several  of  the  characteristic  3-winged  capsules  at  the  top. 

The  twining  movements  of  stem  climbers  are  due  to  the  stimulus  of  gravity  rather 
than  to  contact  stimulus,  and  in  the  majority  of  twining  plants  the  revolving  movements, 
as  seen  from  the  side,  are  from  the  left  to  the  right,  i.e.,  in  a  direction  opposite  to  that  of 
the  hands  of  a  watch  if  represented  diagrammatically. 

various  modifications,  their  relation  to  light  would  be  very  un- 
equal. Sometimes  the  shoot-axis  may  share  with  the  leaves  the 
work  of  assimilation,  as  in  the  case  of  certain  green  stems.  Then 
again  there  are  cases  in  which  the  leaves  are  reduced,  and  the 
work  of  assimilation  is  carried  on  exclusively  by  the  shoot-axis, 
as  in  most  Cactaceae,  certain  marsh-plants,  and  others.  On  the 


MORPHOLOGY  OF  HIGHER  PLANTS. 


323 


other  hand,  the  shoot-axis  may  be  modified  so  as  to  increase  the 
assimilating  surface,  as  by  a  flattening  of  the  axis,  as  in  some  of 
the  Cacti,  the  leaves  being  suppressed  or  considerably  reduced. 


FlG.  181.  Bryonia  dioica.  a,  young,  spirally  coiled  tendril;  b,  expanded  and  irritable 
tendril;  c,  tendril  which  has  grasped  a  support;  d,  tendril  which  has  not  grasped  a  sup- 
port, and  has  undergone  the  old-age  coiling. — After  Pfeffer. 

Branches  are  not  infrequently  modified  to  hard,  pointed,  and 
spiny  structures,  as  in  the  Japanese  quince,  when  they  are  spoken 
of  as  thorns.  Leaves  and  even  flowers  may  arise  upon  thorns, 
which  shows  that  they  are  modified  branches. 


324  A  TEXT-BOOK  OF  BOTANY. 

A  number  of  plants  ascend  into  the  air  on  other  plants,  or 
other  objects  which  serve  as  supports,  either  by  attaching  them- 
selves to  them  or  by  twining  around  them,  when  they  are  dis- 
tinguished as  twiners  and  climbers.  TWINERS  ascend  by  a  special 
circumnutating  movement  of  the  stem,  as  in  the  morning  glory, 
Menispermum  (Fig.  180),  etc.  CLIMBERS,  however,  ascend  by 
means  of  special  structures,  as  the  aerial  roots  of  the  ivy  (root 
climbers)  ;  or  they  may  climb  by  means  of  leaves,  as  in  Clematis 
(leaf  climbers)  ;  still  others  climb  by  means  of  tendrils,  as  in  the 
grape  and  Bryonia  (tendril  climbers)  (Fig.  181)  ;  and  again 
plants  may  climb  by  means  of  hooked  hairs  or  spines,  as  in  Rubus, 


FIG.  182.  Rhizome  of  Podophyllum  representing  three  years'  growth:  ba,the  terminal 
bud  of  last  year;  b2,  the  corresponding  one  of  the  present  year;  B.the  terminal  one  of  the 
entire  rhizome  will  develop  in  the  spring  of  next  year.  L1  and  L2  indicate  the  scars  of  aerial 
leaves  of  the  two  preceding  years'  growth;  bl  and  b2,  latent  buds. — After  Holm. 

Rosa,  etc.  The  tendrils,  which  are  thread-like  modifications  of  the 
stem,  are  in  some  cases  provided  with  disk-like  atachments  for 
holding  the  plant  in  position,  as  in  the  Virginia  creeper.  Twiners 
and  climbers  are  sometimes  spoken  of  as  LIANES  (lianas),  particu- 
larly those  of  tropical  regions,  where  they  form  a  prominent 
feature  of  the  forest  vegetation.  The  lianes  usually  have  rope- 
like,  woody  stems,  the  formation  of  leaves  being  either  suppressed 
or  retarded,  and  they  often  run  for  long  distances  over  the  ground 
and  climb  to  the  tops  of  the  tallest  trees.  They  are  also  frequently 
characterized  by  an  anomalous  stem-structure,  the  tracheae  being 
very  large. 

Stems  vary,  furthermore,  in  size  and  form.    While  most  stems 
are  more  or  less  cylindrical  or  terete,  other  forms  also  occur,  as 


MORPHOLOGY  OF  HIGHER  PLANTS. 


323 


the  flattened  stems  in  the  Cactacese ;  triangular  in  the  Cyperaceae, 
and  quadrangular  in  the  Labiatse  and  Scrophulariaceae. 

Hypogeous  Shoots. — While  most  stems  attain  a  more  or  less 
erect  position,  as  in  trees  and  shrubs,  there  are  others  which 'bend 
over  to  one  side,  or  lie  prostrate  on  the  ground,  and  in  some  cases 


FIG.  183.  Polygonatunt  multiflorum,  a  plant  growing  in  the  Northern  Hemispheres  and 
Japan  and  producing  a  rhizome  resembling  our  Solomon's  Seal  (Polygonaium  biftorum). 
A,  rhizome  placed  artificially  higher  in  the  soil  than  the  normal  depth;  its  continuation 
shoot  has  grown  downwards.  B,  rhizome  placed  deeper  than  the  normal  depth;  its  con- 
tinuation shoot  has  grown  upwards.  The  dotted  lines  at  n  indicate  the  amount  of  annual 
growth  in  the  rhizomes  A  and  B.  C,  a  seedling  rhizome.  At  the  right  is  the  seed,  which 
encloses  the  haustorial  end  of  the  cotyledon;  H,  primary  root;  n,  lateral  roots  arising  within 
the  axis  of  the  shoot;  a,  posterior  side  of  cotylar  sheath;  v,  anterior  side  of  the  same;  b,  c, 
katophyls  (or  leaves  on  hypogeous  shoots)  on  the  axis  of  the  seedling. — A  and  B,  after 
Rimbach;  C,  after  Irmisch.  (From  Goebel's  "  Organography  of  Plants.") 

produce  roots  from  the  nodes,  as  in  Mentha  spicata  (Fig.  184). 
These  latter  are  known  as  STOLONS  or  runners. 

Furthermore,  the  stems  of  a  number  of  plants  grow  under- 
ground, and  these  are  known  as  RHIZOMES  or  ROOT-STOCKS  (Figs. 
182-190)  ;  from  the  upper  portion  of  the  nodes  overground 
branches  arise  which  bear  leaves  (so  that  the  work  of  assimilation 


A  TEXT-BOOK  OF  BOTANY. 


may  be  carried  on)  as  well  as  flowers,  and  from  the  lower  surface, 
roots  (Fig.  182). 

While  most  rhizomes  are  perceptibly  thickened,  and  more  or 
less  fleshy  when  fresh,  as  Sanguinaria,  in  other  instances  they  are 
of  the  ordinary  thickness  of  the  overground  stem. 


FIG.  184.  Plant  of  spearmint  (Mentha  spicata)  showing  procumbent  stems  or  leafy 
runners  from  which  roots  are  developed  at  the  nodes,  and  one  erect  branch  at  the  left  from 
which  a  new  plant  will  be  developed. 

There  are  some  rhizomes  that  are  excessively  thickened,  as 
in  the  common  white  potato  (Fig.  185),  and  these  are  called 
TUBERS.  The  so-called  "  eyes "  are  small  buds  covered  with 
small,  scale-like  leaves  which  develop  into  shoots.  Tubers  should 


MORPHOLOGY  OF  HIGHER  PLANTS. 


327 


not  be  confounded  with  tuberous  roots,  as  those  of  the  sweet 
potato  and  jalap,  for  these  latter  have  the  morphological  char- 
acters of  roots  (compare  Figs.  185  and  186). 

Instead  of  the  node,  or  internode,  or  both,  becoming  exces- 
sively thickened,  they  may  be  reduced  in  size  and  crowded  upon 


FIG.  185.  A  potato  plant  grown  from  seed  and  showing  the  branches  upon  which  the 
potato  tubers  are  formed,  r,  primary  root;  ct,  cotyledons;  c,  hypocotyl;  f,  foliage  leaves; 
f',  a  primary  branch  the  summit  of  which  has  developed  foliage  leaves;  e'c,  scales  on  upper 
portion  of  primary  branch;  e'c',  scales  representing  the  eyes  of  the  potato  tubers  formed 
from  the  swollen  branches;  br,  buds  formed  in  the  axils  of  the  scales  on  the  tubers;  r',  sec- 
ondary roots  formed  on  the  stem  branches. — After  Duchartre. 

each  other,  the  leaves  at  the  same  time  becoming  thickened  and 
filled  with  nutriment.  Such  a  modified  stem  and  leaves,  as  in  the 
onion  and  tulip,  is  called  a  BULB  (Fig.  188).  Bulbs  are  sometimes 
produced  in  the  axils  of  the  leaves  of  overground  stems,  as  in  some 
lilies,  and  are  then  called  bulbils  or  bulblets.  They  are  also  found 
in  Allium  forming  what  are  commonly  known  as  "  onion  sets." 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  1 86.  Several  tubers  formed  by  a  2-year  non-flowering  plant  of  A  conitum  Napellus, 
gathered  in  September.  The  parent  tuber  on  the  right  shows  a  portion  of  the  overground 
stem  and  a  small  bud  (k);  to  the  left  has  been  developed  an  offspring  tuber  connected  by 
the  branch  (a) ;  K,  nearly  full  grown  bud  which  will  produce  the  foliage  stem  of  the  growing 
plant  the  succeeding  year.  The  long,  filiform  and  branching  roots  are  in  the  nature  of  true 
root  branches. — After  Meyer. 

Bulbs  and  tubers  serve  not  only  as  storage-organs  and  carry  the  life 
of  the  plant  over  from  one  season  to  another,  but  may  form,  as  in 


MORPHOLOGY  OF  HIGHER  PLANTS.  329 

bulblets,  an  important  means  of  distributing  the  plants.  The 
thickened  fleshy  stems  of  Cactacese  are  also  regarded  as  storage- 
organs. 

A  CORM  is  intermediate  between  a  true  tuber  and  a  bulb ; 
it  is  more  in  the  nature  of  a  thickened  internode,  being  surrounded 
in  some  cases  by  thin,  membranous  scales,  as  in  Crocus  and 
Colchicum. 

The  function  of  the  vegetative  shoot  is  to  absorb  nutrition 
from  the  earth  as  well  as  from  the  air.  The  shoot  may  be  AERIAL 
or  SUBTERRANEAN.  Some  plants  possess  only  aerial  shoots  or 
LIGHT-SHOOTS,  as,  for  instance,  trees,  shrubs,  and  herbs  that  flower 


FIG.  187.  Rhizome  of  African  ginger  showing  scars  of  overground  branch  (Ls)  and 
buds  (k).  The  more  or  less  parallel  lines  represent  leaf-scars  and  scars  of  bud-scales,  and 
the  small  circles,  root-scars. — After  Meyer. 

but  once.  Other  plants  possess  both  aerial  and  subterranean 
shoots,  and  of  these  the  subterranean  shoot  may  exhibit  some  of 
the  peculiarities  of  roots,  in  that  they  do  not  develop  chlorophyll 
and  produce  secondary  roots  for  the  purpose  of  obtaining  nutri- 
tive substances  from  the  soil.  The  SUBTERRANEAN  SHOOTS  are 
generally  destitute  of  true  leaves  and  are  furnished  only  with 
membranous  or  sometimes  thick,  fleshy  leaves  which  are  bladeless, 
pale,  scale-like,  or  tubular. 

Depending  upon  the  duration  of  the  shoot  (or,  better,  the 
stem),  plants  are  divided  into  HERBS,  SHRUBS,  and  TREES.  In 
herbs  the  aerial  shoots  are  herbaceous,  while  in  shrubs  and  trees 
they  become  woody  and  persist  throughout  many  years. 


330 


A  TEXT-BOOK  OF  BOTANY. 


Many  of  the  herbs  have  subterranean  shoots,  but  these  are 
generally  absent  from  woody  plants,  excepting  in  Sambucus, 
Ailanthus,  Calycanthus,  etc.  The  herbs  may  be  further  sub- 
divided as  annual,  biennial,  and  perennial. 


FIG.  188.  Longitudinal  section  through  a  germinating  bulb  of  Tulipa  prcecox:  h, 
the  brown  enveloping  membrane;  k,  the  flattened  stem  which  forms  the  base  of  the  bulb 
and  bears  the  bulb-scales  (sh);  si,  the  elongated  part  of  the  stem  which  bears  the  foliage- 
leaves  (l'l')t  and  terminates  in  the  flower;  c,  the  ovary;  p,  perianth;  a,  anthers;  2,  a  lateral 
bulb  in  the  axil  of  the  youngest  bud-scale,  which  develops  into  the  bud  of  next  year's  bulb; 
w,  the  roots  which  arise  from  the  fibrovascular  bundles  at  the  base  of  the  bulb. — After 
Sachs. 

In  ANNUAL  herbs  the  individual  possesses  only  aerial  shoots 
and  the  plant  sets  fruit  the  same  year  that  the  individual  has  de- 
veloped from  the  seed.  In  BIENNIAL  herbs  the  plant  does  not 
produce  flowers  until  the  second  season.  The  PERENNIAL  herbs, 


MORPHOLOGY  OF  HIGHER  PLANTS.  331 

on  the  other  hand,  develop  flowers  continuously  for  many  (or  at 
least  several)  years  and  also  produce  subterranean  shoots,  such 
as  creeping  rhizomes,  tubers,  bulbs,  etc. 


FIG.  189.  Upper  portion  of  rhizome  of  Gentiana  lutea  showing  the  structure  of  terminal 
buds:  A,  terminal  bud  cut  open  to  show  the  foliage  leaves  (b),  which  lie  close  to  one  another, 
leaving  only  a  narrow  canal  (s)  in  the  middle.  B,  four-angled  bud  removed  from  A,  showing 
the  foliage  leaves  having  a  strongly  developed  basal  region  (s)  and  relatively  small  lamina  (sp) . 
C,  a  small  bud  removed  from  the  axis  of  the  young  leaves  (B).  D,  upper  portion  of  rhizome 
of  a  flowering  plant  showing  the  stem  base  (S)  and  several  buds  (k).  E,  upper  portion  of 
rhizome  of  a  plant  6  years  old  showing  scar  (n)  of  the  flowering  branch  and  the  strongly 
developed  side  branches  with  terminal  buds  (k).  The  annulations  are  scars  formed  from 
the  bud  scales  which  have  dropped  off. — After  Meyer. 

The  roots  of  annuals,  biennials,  and  perennials  differ  in  a  num- 
ber of  particulars.  In  the  annuals,  belonging  to  the  monocoty- 
ledons, the  roots  are  fibrous,  possessing  numerous  lateral  branches, 
whereas  in  the  annuals  belonging  to  the  dicotyledons  only  the 


332  A  TEXT-BOOK  OF  BOTANY. 

primary  roots  develop.  The  biennials  are  nearly  all  dicotyledons 
and  have  a  persistent  primary  root  which,  while  usually  slender, 
may  become  fleshy,  as  in  Beta.  In  the  perennials,  on  the  other 
hand,  we  find  a  number  of  different  types  of  roots,  varying  from 
the  slender  aerial  roots  of  epiphytes  to  the  smaller  tuberous, 
fleshy  roots  of  many  terrestrial  plants,  and  the  peculiar  roots  of 
parasites. 

ALTERATIONS  IN  THE  FORM  OF  PLANTS. — The  shoot,  in  its 


FIG.  190.  Specimens  of  "orris  root"  of  commerce  consisting  of  peeled  pieces  of  the 
rhizomes  of  Iris  florentina.  The  rhizomes  are  mostly  dichotomous,  the  branches  becoming 
obconical  and  of  characteristic  shape.  The  large  circular  areas  terminating  the  rhizomes 
are  scars  of  stem  bases,  while  the  small  black  dots  on  the  surface  are  scars  from  attachment 
of  roots. 

course  of  development,  is  subject  to  a  great  many  hostile  external 
conditions,  and  there  results  more  or  less  mutilation  and  alteration 
in  the  form  of  the  plant.  One  of  the  most  destructive  influences 
to  plants  is  that  of  strong  winds  when  they  attain  the  the  velocity 
of  gales.  They  stunt  the  growth  of  woody  plants  and  cause  the 
branches  to  assume  a  horizontal  position  (Fig.  191).  This  un- 
usual growth  is  further  accentuated  if  at  times  during  the  winter 
they  are  covered  with  snow  and  sleet.  If  they  grow  in  close 


MORPHOLOGY  OF  HIGHER  PLANTS. 


333 


334  A  TEXT-BOOK  OF  BOTANY. 

proximity  their  limbs  will  lash  .each  other,  causing  a  flattening 
of  the  top  which  is  very  characteristic  in  the  groves  of  trees  on 
the  sea  coast.  In  this  way  it  is  possible  for  the  whip-like  branches 
of  the  birch  to  mutilate  even  the  tops  of  the  fir  tree,  changing 
their  spire-like  summits  to  deliquescent  crowns.  Injuries  causing 
an  alteration  in  the  form  of  plants  are  also  caused  by  ruminating 
animals  and  leaf-devouring  insects. 

GALLS. — These  are  abnormal  developments  on  the  young  twigs, 
leaves,  and  flowers,  being  caused  by  the  punctures  and  presence 
of  the  deposited  ova  of  quite  a  variety  of  insects.  Galls  vary  in 
size,  form,  and  general  appearance.  They  are  only  capable  of 
being  produced  either  in  meristematic  cells  or  in  tissues  that  are 
capable  of  exercising  this  function.  They  are  never  formed  on 
mature  stems,  leaves,  or  flowers.  The  older  parts  may  be  eaten 
and  destroyed  by  insects,  but  they  are  not  capable  of  being  meta- 
morphosed. In  these  growing  tissues  the  mother  insect  lays  her 
eggs,  which  upon  further  growth,  either  through  the  secretion  of 
particular  substances  or  otherwise,  determine  the  direction  of 
growth  of  the  cells  and  the  final  product  which  shall  be  formed. 

As  has  already  been  stated,  galls  show  considerable  variation, 
and,  as  there  are  many  hundreds  of  distinct  galls,  various  attempts 
have  been  made  to  classify  them.  Kuster  has  proposed  an  ana- 
tomical classification  as  follows:  i.  Galls  in  which  there  may  be 
an  enlargement  of  cells,  but  no  cell  multiplication ;  2.  Soft  galls, 
composed  of  numerous  cells,  the  resulting  product  being  more  or 
less  fleshy ;  3.  Hard  galls,  in  which  there  is  an  active  cell  division, 
and  sclerotic  modification  of  the  external  layer  so  as  to  prevent 
the  drying  up  of  the  gall  in  summer  and  to  guard  against  attack 
by  birds  and  other  animals.  Modry  ( Beitrage  zur  Gallenbiologie) , 
on  the  basis  of  Kuster's  classification,  has  given  a  very  compre- 
hensive review  of  the  various  structural  (both  external  and  in- 
ternal) characters  of  the  various  groups  of  zoo-cecidia. 

In  a  classification  of  galls  Thomas  has  suggested  as  a  class 
name  for  these  structures  the  word  CECIDIEN  (meaning  nut-gall). 
The  cecidien  or  galls  are  divided  into  two  main  groups,  as  fol- 
lows :  I.  PHYTO-CECIDIEN  or  fungus  galls,  including  the  parasitic 
fungi  which  cause  a  metamorphosis  in  the  shoots  of  larger  shrubs 
and  trees  forming  the  structures  commonly  known  as  "  Witches' 


MORPHOLOGY  OF  HIGHER  PLANTS.     335 

brooms."  Galls  exhibiting  strange  forms  are  also  produced  by 
the  Gymnosporangia  on  the  stems  of  the  common  juniper,  the 
leaves  of  the  mountain  ash,  etc.  In  this  group  would  also  be 
included  the  CROWN-GALLS  occurring  on  a  large  number  of  plants, 
as  grapes,  peach,  juniper,  and  field  crops.  At  one  time  it  was 
thought  that  these  galls  were  due  to  frosts  or  mechanical  injuries. 
The  extended  researches  of  Smith  (Bulletin  No.  213,  Bureau  of 
Plant  Industry,  U.  S.  Department  of  Agriculture)  have  shown 
that  crown-galls  are  in  the  nature  of  bacterial  diseases.  He 
showed  that  crown-galls  not  only  resembled  malignant  animal 
tumors,  especially  sarcoma,  but  demonstrated  that  this  resemblance 
was  more  than  superficial.  II.  ZOO-CECIDIEN,  or  those  galls  which 
are  formed  within  the  body  of  the  plant  and  due  to  attacks  by 
insects.  This  group  includes  by  far  the  larger  number  of  galls, 
and  is  further  subdivided  according  to  the  various  animal-groups 
causing  them. 

Galls  differ  in  structure,  but  the  general  nature  of  the  anat- 
omy may  be  seen  in  a  study  of  the  common  "  ink  ball "  or  "  ink 
gall,"  formed  on  Quercus  coccinea  by  Cynips  aciculata.  These 
galls  are  produced  during  the  summer  months  on  the  young 
branches  and  sometimes  on  the  acorns.  When  mature  they  fall 
from  the  trees  and  are  nearly  globular  in  shape,  varying  from  20 
to  30  mm.  in  diameter.  They  are  solid  throughout  and  of  the 
consistency  of  the  pulp  of  a  green  apple.  Externally  they  are 
smooth,  and  are  colored  a  mottled  green,  yellow,  or  brownish- 
red.  At  this  stage  they  are  made  up  of  three  distinct  zones: 
( i )  A  central  area,  made  up  of  nearly  isodiametric  starch-bear- 
ing, parenchymatous  cells.  (2)  The  middle  zone  is  composed 
of  radially  elongated  parenchymatous  cells,  possessing  thick, 
porous  cellulose  walls  containing  a  lining  of  protoplasm  and  a  few 
starch  grains.  With  the  development  of  the  egg  of  the  insect 
there  also  appear  in  the  cells  of  this  middle  zone  numerous  starch 
grains  closely  resembling  those  found  in  the  central  zone.  (3) 
An  external  layer  made  up  of  irregular  parenchymatous  cells, 
somewhat  collenchymatic  in  character,  with  a  lining  of  protoplasm 
as  in  the  cells  of  the  middle  zone. 

In  some  studies  on  the  origin  of  tannin  in  galls  Kraemer  (Bot. 
Gas.,  1900,  p.  275)  showed  that  in  the  "  ink  gall  "  there  are  three 


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A  TEXT-BOOK  OF  BOTANY. 


stages  in  their  development,  corresponding  to  the  life  periods  of 
the  insects  and  dianges  in  the  constituents  of  the  cells:  (i) 
When  the  galls  are  first  formed  and  the  larva  is  beginning  to  de- 
velop, the  cells  of  the  outer  zone,  as  well  as  those  of  the  central 


FIG.  192.  Transverse  section  of  one  of  the  collateral  mestome  strands  of  the  stem  of 
Viola  tricolor  arvenis:  o,  portion  of  cells  of  pericycle;  e,  endodermis;  1,  leptome  or  sieve 
cells,  in  among  which  are  some  collenchymatous  cells  (c) ;  m,  cambium;  t,  spiral  tracheae  or 
vessels;  g,  strongly  lignified  tracheae;  rp,  medullary  ray  cells,  the  walls  of  which  are  com- 
posed of  cellulose;  rs.  medullary  ray  cells  the  walls  of  which  are  strongly  lignified;  s, 
strongly  lignified  cells  separating  the  mestome  strands ;  c,  collenchyma;  p,  pith. 

zone,  contain  numerous  small  starch  grains.  (2)  When  the  in- 
sect reaches  the  chrysalis  stage  the  starch  in  the  cells  near  the 
middle  of  the  galls  is  replaced  in  part  by  gallic  acid,  while  the 
cells  at  the  center  and  near  the  periphery  contain  masses  of  tannic 


MORPHOLOGY  OF  HIGHER  PLANTS.  337 


W 


FIG.  193.  Collateral  fibrovascular  bundle  in  Menispermum:  C,  cortex;  B,  bast 
fibers;  St,  stone  cells  connecting  groups  of  bast  fibers;  S,  sieve;  M,  cambium;  T,  tracheae; 
W,  wood  fibers;  R,  medullary  rays;  P,  pith. 


22 


338  A  TEXT-BOOK  OF  BOTANY. 

acid.  (3)  When  the  winged  insect  is  developed  nearly  all  of 
the  cells  contain  amorphous  masses  of  tannic  acid  with  some 
adhering  crystals  of  gallic  acid.  After  the  insect  has  emerged 
from  the  gall  the  constituents  again  undergo  change,  depending 
largely  on  the  presence  of  moisture,  when  the  tannic  acid  is  changed 
into  more  or  less  insoluble  products  and  the  galls  become  more 
porous. 

THE  INNER  STRUCTURE  OF  THE  STEM. 

If  we  make  a  transverse  section  of  a  young  herbaceous  stem, 
we  observe  a  differentiation  of  the  tissues,  which  in  several  re- 
spects agrees  with  that  of  the  root  previously  described.  In  the 
primary  structure  of  the  stem  the  following  tissues  are  to  be 
noticed :  The  outermost  layer  is  the  epidermis  with  a  more  or 
less  distinct  cuticle ;  the  second  is  the  cortical  parenchyma,  fre- 
quently having  strands  of  collenchyma  near  the  epidermis.  The 
cortex  often  contains  secretory  cells  or  receptacles,  and  not  infre- 
quently the  innermost  layer  is  differentiated  as  an  endodermis. 
The  latter  surrounds  the  so-called  pericycle,  a  sheath  consisting 
of  more  or  less  distinct  stereomatic  strands,  either  forming  a 
closed  sheath  or  merely  representing  isolated  arches  outside  the 
leptome  of  the  stele.  Inside  the  pericycle  we  observe  the  mestome 
strands  constituting  mostly  one  circular  band  (in  cross  section) 
in  the  Dicotyledons  and  Gymnosperms,  or  several  more  or  less 
concentric  bands  in  the  Monocotyledons.  The  mestome  strands 
or  fibrovascular  bundles  may  be  collateral  (Figs.  192-194),  bi- 
collateral  or  concentric,  the  last  of  which  being  found  only  in  the 
Monocotyledons  (Fig.  195)  and  Ferns  (Fig.  56). 

In  the  DICOTYLEDONS  the  collateral  fibrovascular  bundles  occur 
most  frequently  and  consist  of  three  distinct  portions,  viz.,  phloem, 
xylem,  and  cambium.  The  phloem  consists  of  sieve  tubes,  com- 
panion cells  (or  accompanying  cells),  and  cambiform.  The  last 
two  are  thin-walled  parenchymatous  cells,  those  of  the  cambiform 
being  considerably  elongated.  In  addition  there  may  be  included 
in  the  phloem  the  stereomatic  tissues  or  bast  fibers,  which  are  not 
infrequently  well  developed.  The  xylem  includes  tracheae  or 
vessels,  tracheids,  wood  parenchyma,  and  libriform  or  wood  fibers. 

To  the  student  some  confusion  may  arise  as  to  the  apparent 
indiscriminate  use  of  the  terms,  leptome  and  hadrome,  the  former 


MORPHOLOGY  OF  HIGHER  PLANTS 


FIG.  194.  Dicotyledonous  stem  structure.  Transverse  section  through  menisperrnum 
rhizome:  E,  epidermis;  K,  sub-epidermal  cork;  C,  cortex;  B,  bast  fibers;  S,  sieve;  ST, 
Stone  cells;  CA,  cambium;  T,  vessels;  W,  wood  fibers;  M,  medullary  ray  cells;  P,  pith. 


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A  TEXT-BOOK  OF  BOTANY. 


FIG.  195.  Monocotyledonous  stem  structure.  Transverse  section  of  convallaria 
rhizome:  E,  epidermis;  H,  hypodermis  composed  of  collenchyma;  C,  cortex;  EN,  endo- 
dermis;  S,  perihadromatic  sieve;  T,  tracheae  or  vessels;  P,  parenchyma.  The  bundles  are 
of  the  collateral  and  concentric  types. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


341 


being  used  as  being  apparently  synonymous  with  phloem  and  the 
latter  being  equivalent  to  xylem.  As  a  matter  of  fact,  these  terms 
are  not  equivalent,  the  phloem  proper  including  bast  fibers  in 
addition  to  leptome ;  and  the  xylem  being  composed  of  wood 
fibers  in  addition  to  hadrome;  nor  is  the  fibrovascular  bundle 
synonymous  with  mestome  strand,  as  the  former  includes  not  only 
the  conducting  tissues  but  the  mechanical  tissues  as  comprised  in 
the  xylem  and  phloem ;  while  the  mestome  strand  includes  only 
the  conducting  cells  comprised  in  the  leptome  and  in  the  hadrome, 
there  being  no  sclerenchymatous  fibers  present.  The  following 
table  will  doubtless  make  clear  to  the  student  the  relationship 
of  these  tissues  to  each  other: 


Mestome  or 

vascular 

bundle 


Leptome  or 
Sieve  portion 


Hadrome  or 
Tracheal  portion 


Stereome  or 
Bast  fibers 

f  Sieve  tubes 

<  Accompanying  cells   \ 
(.Cambiform  J 

Cambium 

[Tracheae 

<  Tracheids 

I  Wood  parenchyma 

Libriform  or 
Wood  fibers 


Phloem 


Fibro- 
vascular 
bundle 


Xylem 


When  the  collateral  mestome  strand  increases  in  thickness,  the 
increase  is  due  to  the  activity  of  the  cambium,  here  called  the 
INTRAFASCICULAR  CAMBIUM,  which  then  develops  phloem  or  lep- 
tome outwardly  and  xylem  or  hadrome  inwardly.  Between  the 
primary  mestome  strands  there  is  frequently  a  procambium, 
which  connects  these  strands  with  each  other,  and  which  gener- 
ally gives  rise  to  secondary  mestome  strands,  or  the  connection 
may  be  effected  by  means  of  the  intrafascicular  cambium,  which 
often  extends  itself  from  one  strand  to  another  and  develops  lep- 
tome and  hadrome,  as  in  the  primary  strands ;  such  cambium  is 
distinguished  as  INTERFASCICULAR  CAMBIUM  and  is  commonly 
referred  to  as  the  CAMBIUM  RING. 

The  BICOLLATERAL  mestome  strands  or  fibrovascular  bundles, 
characteristic  of  some  Dicotyledons  (Labiatse,  Solanacese,  Cucurbi- 
tacese,  etc.),  differ  from  the  COLLATERAL  type  by  having  a  leptome 


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A  TEXT-BOOK  OF  BOTANY. 


strand  developed  on  the  inner  face  of  the  hadrome;  thus  each 
mestome  strand  carries  two  strands  of  leptome  (Fig.  197,  C).  In 
the  CONCENTRIC  mestome  strands  the  leptome  may  encircle  the 
hadrome,  as  in  the  Ferns  (Fig.  56),  or  the  hadrome  may  partly 


Kt 


Hr 


St 


Sr 


Mt 


Mi 


FIG.  196.  The  outer  bark  and  part  of  trie  inner  bark  of  Rhamnus  Purshianus  in  trans- 
verse, radial-longitudinal,  and  tangential-longitudinal  sections.  Me,  transverse  section  of 
inner  bark;  Mt,  tangential-longitudinal  section  of  inner  bark;  Mr,  radial-longitudinal  section 
of  inner  bark;  Sc,  transverse  section  of  stone  cell  area;  St,  tangential-longitudinal  section 
of  stone  cell  area;  Sr,  radial-longitudinal  section  of  stone  cell  area;  He,  transverse  section 
of  outer  layers  of  cortex;  Hr,  radial-longitudinal  section  of  outer  layers  of  cortex.  Kc,  Kt, 
Kr,  transverse,  tangential-longitudinal,  and  radial-longitudinal  sections  of  cork;  b,  bast 
fibers;  f,  crystal  fibers;  p,  parenchyma;  e,  sieve;  sk,  stone  cells;  m,  medullary  ray  cells; 
c,  collenchyma. 

(as  in  the  rhizomes  of  many  Monocotyledons)  surround  the  lep- 
tome (Fig.  195).  While  thus  the  collateral  type  of  strand  or 
bundle  occurs  in  both  Monocotyledons  (Fig.  195)  and  Dicotyle- 
dons (Figs.  192,  193),  etc.,  the  presence  of  a  cambium  is  found 
only  in  the  Dicotyledons  and  occurs  extremely  seldom  in  the  Mono- 


MORPHOLOGY  OF  HIGHER  PLANTS. 


343 


cotyledons.  The  central  portion  of  the  stele  is  frequently  differ- 
entiated into  a  PITH  of  parenchymatic  structure,  the  cells  of  which 
often  contain  large  quantities  of  starch.  In  addition  in  the  pith, 
we  often  find  the  same  types  of  secretory  cells  or  receptacles  as 
occur  in  the  cortex  (as  in  Apocynum).  The  pith  may  constitute 
a  homogeneous  tissue  or  be  broken,  as  in  Phytolacca,  Carya, 
Halesia,  etc.,  where  a  longitudinal  section  shows  the  pith  divided 
into  a  row  of  broad  cavities  formed  by  a  separation  of  the  cells 
as  a  result  of  the  rapid  longitudinal  growth  of  the  stem 

Finally  it  may  be  mentioned  that  cork  is  of  frequent  occur- 
rence, especially  upon  stems  that  persist  more  than  one  year. 
The  cork  may  arise  in  the  epidermis  itself,  or  it  may  develop  in 
the  hypodermal  strata  of  the  cortex,  or  in  still  other  cases  we  find 
its  development  much  deeper,  even  within  the  pericycle. 


FIG.  197.  Schematic  representation  of  different  types  of  mestome  strands  or  fibro- 
vascular  bundles:  s,  sieve;  t,  tracheae  or  vessels;  e,  position  of  the  earliest  tracheae  formed; 
a,  radial  bundle  or  mestome  strand;  b,  collateral  bundle;  c,  bicollateral  bundle;  d  and  e, 
concentric  bundles. — After  Meyer. 

In  regard  to  the  increase  in  thickness,  the  stem  develops  much 
like  the  root,  as  in  the  throwing  off  the  peripheral  tissues  extend- 
ing from  the  epidermis  to  the  endodermis,  or  of  the  epidermis 
and  adjoining  cortex,  the  displaced  tissues  are  replaced  by  strata  of 
cork  and  secondary  cortex.  The  mestome  strands  in  the  stem, 
however,  grow  in  a  more  regular  manner  than  is  the  case  with 
those  of  the  root,  as  is  seen  in  the  very  distinct  and  frequently 
very  regular  layering  of  the  tissues  of  woody  stems,  forming  the 
so-called  "  Annual  Rings,"  where  each  ring  represents  the  growth 
that  occurs  during  a  single  year.  The  development  of  these 
annual  rings  depends  especially  upon  the  fact  that  the  growth 
of  the  perennial  stem  does  not  take  place  continuously,  but  is  in- 
terrupted during  certain  periods  of  the  season,  for  instance  dur- 
ing the  winter  or  during  the  dry  seasons  of  tropical  climates. 
And  since  the  tissues  which  are  formed  at  tHe  beginning  of  each 


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A  TEXT-BOOK  OF  BOTANY. 


season's  growth  are  distinct  from  those  already  formed  during 
the  previous  season  in  both  color  and  structure  of  the  wood  (espe- 
cially in  the  thickness  of  cell-walls  and  the  width  of  the  tracheae 
or  vessels),  we  perceive  in  this  manner  distinct  zones  of  wood, 
or  the  "  annual  rings  "  as  they  are  called,  the  larger  vessels  with 
thin  walls  being  produced  in  the  spring  and  early  summer. 

Various  abnormal  stem-structures  are  known  which  are  due 


FIG.  198.  Transverse  section  of  wood  of  Rhamnus  Frangula  showing  that  the  annular 
rings  seen  in  woody  portion  of  plants  is  due  to  a  difference  in  the  nature  and  structure  of  the 
cells  formed  in  the  spring  and  in  the  fall.  In  the  spring  numerous  large  tracheae  or  vessels 
(v)  are  formed,  whereas  in  the  fall  very  few  vessels  and  mostly  wood  fibers  are  developed, 
the  cells  of  these  being  smaller  as  they  approach  the  end  of  the  year's  growth.— After  Rossmann. 

to  certain  peculiarities  in  the  growth  in  thickness  of  stems.  These 
are  especially  noticeable  in  lianes.  In  some  of  the  Monocotyledons, 
as  in  Dracaena,  Yucca,  Agave  and  Aloe,  we  find  a  secondary  in- 
crease in  growth  of  the  stems. 

In  summarizing  the  root  and  stem  structures  of  Monocotyle- 
dons and  Dicotyledons  the  following  general  facts  should  be 
borne  in  mind.  Monocotyledonous  stems  resemble  Monocotyle- 
donous  roots  except  that  the  fibrovascular  bundle  or  mestome 


MORPHOLOGY  OF  HIGHER  PLANTS. 


345 


strand  of  the  former  is  concentric,  whereas  in  the  latter  it  is 
radial.  The  primary  structure  of  Dicotyledonous  roots  is  much 
the  same  as  in  Monocotyledonous  roots.  The  primary  structures 
of  Dicotyledonous  stems  resemble  the  primary  structure  in  Dicoty- 
ledonous roots  except  that  the  fibrovascular  bundles  of  the  former 
are  of  the  collateral  type.  The  secondary  structures  of  both  roots 
and  stems  of  Dicotyledons  are  oractically  alike.  The  characteristics 


FIG.  199.  Section  of  a  four-year-old  stem  of  a  pine  cut  in  winter;  q,  view  in  trans-- 
verse section;  1,  radial-longitudinal  section;  t,  tangential-longitudinal  section;  f,  spring 
wood;  s,  fall  wood;  m,  pith;  i,  2,  3,  4,  successive  years'  rings  of  growth  in  which  is  shown 
the  dividing  line;  ms,  medullary  rays  in  transverse  section;  ms1,  ms11,  medullary  rays 
in  radial-longitudinal  section;  ms111,  medullary  rays  in  tangential-longitudinal  section: 
c,  cambium;  b,  bast;  h,  resin-canals;  br,  bork. — After  Strasburger. 

distinguishing  the  primary  and  secondary  structures  of  Dicotyle- 
donous stems  may  be  summarized  as  follows : 

PRIMARY  STRUCTURES. — Epidermis,  hypodermis,  primary  cor- 
tex, endodermis,  pericambium  or  pericycle,  stele  consisting  of 
collateral  fibrovascular  bundles  and  pith. 

SECONDARY  STRUCTURES. — Periderm  derived  from  phellogen; 
secondary  cortex,  consisting  of  parenchyma  and  occasionally 
stone  cells  or  secretory  cells  or  vessels;  phloem  consisting  of 
sieve,  accompanying  cells  and  sometimes  bast  fibers ;  cambium  in 


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A  TEXT-BOOK  OF  BOTANY. 

A  B 


FIG.  200.  Coarse  structure  of  a  number  of  woods  as  seen  with  a  Coddington  lens: 
A,  English  walnut  (Juglans  regia)  showing  the  tracheae  evenly  distributed  in  the  form  of 
pores,  which  can  be  seen  in  the  wood  with  the  naked  eye;  the  medullary  rays  are  rather 
faint  and  arranged  in  closely  radiating,  parallel  rows;  in  the  fall  wood  are  numerous  fine 
transverse  lines  parallel  with  the  annular  markings.  B,  shell-bark  hickory  (Carya  ovata) 
showing  a  row  of  large  tracheae  (g)  in  the  summer  wood  and  somewhat  smaller  tracheae  (g') 
scattered  throughout  the  subsequent  growth;  medullary  rays  numerous,  as  are  also  the 
somewhat  undulating  transverse  lines  (F).  C,  white  or  canoe  birch  (Betula  pendula)  showing 
distinct  annular  rings  and  numerous  medullary  rays  between  which  are  scattered  the  small 
tracheae  indicated  by  black  dots.  D,  chestnut  (Caslanea  dentata)  showing  large  tracheae 
arranged  in  circular  groups,  those  of  the  successive  layers  being  smaller  and  arranged  some- 
what obliquely,  forming  triangular  groups;  medullary  rays  very  faint;  E,  Elm  (Ulmus 
campestris)  showing  tracheae  arranged  in  circles  in  the  summer  wood  and  in  the  later  growth 
a  number  of  broad  more  or  less  undulating  plates  composed  of  very  small  tracheae;  medullary 
rays  quite  distinct;  F,  Cherry  (Prunus  domestica),  tracheae  quite  distinct  in  the  summer 
wood,  forming  several  circular  rows;  medullary  rays  broad  and  distinct. — B,  after  Wiesner; 
the  remainder  after  R.  Hartig. 


MORPHOLOGY  OF  HIGHER  PLANTS.  347 

the  form  of  a  ring  known  as  interfascicular  cambium ;  xylem  com 
posed  of  tracheae,  wood  parenchyma,  usually  wood  fibers  and 
sometimes  tracheids;  medullary  rays  separating  the  collateral 
bundles;  pith  composed  of  parenchyma  and  sometimes  having 
stone  cells  and  secretory  cells  similar  to  those  found  in  the  cortex. 
In  stems  having  bicollateral  bundles,  strands  of  phloem  also*  occur 
on  the  inner  surface  of  the  xylem  rays. 

IMPORTANCE  OF  THE  STUDY  OF  THE  STRUCTURE  OF  WOOD. — 
The  structure  of  stems  in  woody  plants  is  very  characteristic,  not 
only  in  different  families  but  in  genera  and  at  times  in  species. 
In  the  Pinaceae,  for  instance,  the  wood  is  entirely  made  up  of 
tracheids,  the  tracheae  being  wanting.  In  most  of  the  Dicotyledons 
tracheae  are  present,  being  absent  only  in  certain  water  plants  as 
Nymphaeaceae  and  in  Drimys,  a  genus  of  the  Magnoliaceae.  In 
the  Cactaceae  the  secondary  wood  is  provided  with  annular  and 
spiral  tracheids.  In  practical  work,  whether  it  be  in  the  study  of 
plants  for  taxonomic  purposes  or  for  their  industrial  uses,  the 
following  are  some  of  the  observations  that  should  be  made: 
I.  Structure  of  the  walls  and  nature  of  the  perforations  or  mark- 
ings in  the  tracheae  or  vessels.  2.  The  presence  or  absence  and 
relative  distribution  of  libriform  or  wood  fibers  (often  referred 
to  as  wood  prosenchyma).  3.  The  structure  of  the  medullary 
rays  not  only  as  regards  thickening  of  the  walls  and  contents  of 
the  cells,  but  the  number  of  the  cells  both  as  to  width  and  height 
entering  into  the  individual  groups  of  rays.  4.  Wood  paren- 
chyma is  variously  distributed,  the  cells  aggregated  about  the 
vessels  being  distinguished  from  those  that  form  tangential  bands 
separating  the  circles  of  vessels.  The  distribution  of  the  crystals 
is  also  of  importance,  as  they  may  occur  in  isolated  cells  or  in 
superimposed  cells  adjoining  the  wood  fibers  and  form  the  so- 
called  crystal  fibers. 

In  the  study  of  different  commercial  woods  it  is  customary 
in  practice  to  study  the  coarser  features  such  as  can  be  recog- 
nized by  the  help  of  an  ordinary  hand  lens.  In  this  superficial 
study  many  distinctive  characteristics  can  be  readily  determined,  as 
the  nature  of  the  annual  rings,  the  size  of  the  lumina  of  the  ves- 
sels, as  well  as  their  abundance  and  arrangement,  etc.  (Fig.  200). 


348 


A  TEXT-BOOK  OF  BOTANY. 


III.  THE  OUTER  MORPHOLOGY  OF  THE  LEAF. 
Leaves  are  lateral  formations  upon  the  stem  and  their  growth 
is  definite.  They  never  occur  on  other  portions  of  the  plant  than 
stems,  from  the  surface  of  which  they  are  developed.  Leaves 
appear  in  acropetal  succession,  so  that  the  youngest  leaves  occur 
nearest  the  apex  of  the  stem.  Terminal  leaves  are  extremely 
rare,  but  arise  in  some  instances  from  the  flowers  o>f  certain 
Euphorbiaceae. 


FIG.  20 1.  A,  leaf  of  violet  (Viola  tricolor)  showing  broad  lamina,  long  petiole,  and  one 
of  the  palmately-lobed  stipules  at  the  base  of  the  petiole.  B,  C,  stages  In  the  development 
of  the  leaf.  The  lobes  of  the  stipules  (s)  develop  before  the  lamina  (1). 

A  Simple  Leaf  consists  of  a  LAMINA  or  blade,  which  is  usually 
membranous  and  of  a  green  color,  and  a  PETIOLE  or  stalk,  which, 
however,  may  be  wanting  when  the  leaf  is  said  to  be  sessile. 
Leaves  may  also  possess  a  pair  of  leaf-like  structures  at  the  base, 
known  as  STIPULES  (Figs.  201,  204).  The  principal  function  of 
the  latter  appears  to  be  that  of  protecting  the  buds,  as  in  the 
tulip  poplar  (Liriodendron)  (Fig.  204),  although  they  may  be- 
come leaf-like  and  assist  in  the  functions  of  the  lamina,  as  in 
Viola  tricolor  (Fig.  201). 


MORPHOLOGY  OF  HIGHER  PLANTS.  349 

Light  Relation  of  Leaves. — While  the  lamina  of  the  leaf 
appears  to  assume  a  more  or  less  horizontal  position,  it  usually 
inclines  at  such  an  angle  as  to  receive  the  greatest  amount  of  dif- 
fused daylight.  Wiesner  has  shown,  for  instance,  that  when 
plants  are  so  situated  that  they  receive  direct  sunlight  only  for  a 
time  in  the  morning,  and  diffused  daylight  during  the  rest  of  the 
day,  the  position  of  the  upper  surface  is  at  right  angles  to  the 
incident  rays  of  daylight,  and  not  to  that  of  the  rays  of  the 
morning  sun.  This  phenomenon  may  be  studied  in  the  house 
geranium  and  other  window  plants.  In  endeavoring  to  explain  this 
behavior  of  the  leaves,  Frank  assumes  it  to  be  due  to  a  kind  of 
heliotropic  irritability  peculiar  to  dorsiventral  organs,  and  terms 

it  TRANSVERSE    HELIOTROPISM. 

The  stem,  as  well  as  the  petiole  or  stalk  of  the  leaf,  is  also 
influenced  by  the  light,  and  is  said  to  manifest  positive  helio- 
tropism.  Those  parts  of  plants  that  turn  away  from  the  light,  as 
the  aerial  roots  of  the  ivy,  are  said  to  possess  negative  helio- 
tropism. 

Depending  upon  their  relation  •  to  external  agents,  several 
forms  of  leaves  are  distinguished.  In  those  which  assume  a  more 
or  less  horizontal  position  the  two  surfaces  of  the  lamina  are 
quite  different,  and  the  leaves  are  said  to  be  DORSIVENTRAL,  or 
bifacial.  Usually  there  is  a  more  compact  arrangement  or  stronger 
development  of  chlorophyll  tissue  on  the  upper  or  ventral  surface, 
while  on  the  lower  or  dorsal  surface  the  veins  stand  out  more 
prominently,  and  there  is  a  greater  number  of  stomata. 

In  contrast  with  this  type  of  leaf  may  be  mentioned  those 
which  grow  edgewise  and  in  which  both  surfaces  of  the  leaf  are 
more  or  less  alike,  as  in  the  Eucalypts  and  Acacias  of  Australia. 
In  Iris  and  Calamus,  the  leaf-like  organ  is  actually  not  the  blade, 
but  merely  a  part  of  the  dorsal  face,  which,  in  the  bud,  has  already 
pushed  out  so  as  to  exceed  the  apex.  Such  leaves  are  called 
SWORD-SHAPED  and  are  frequently  referred  to  as  EQUITANT.  The 
leaves  of  certain  species  of  Juncus,  Carex  and  some  of  the  grasses 
are  commonly  spoken  of  as  CYLINDRIC.  Such  leaves  are,  how- 
ever, only  apparently  cylindrical,  since  the  ventral  surface  is 
often  distinct,  though  much  narrower  than  the  dorsal.  They 
are  also  frequently  hollow. 


350  A  TEXT-BOOK  OF  BOTANY. 

Functions  of  the  Leaf. — When  we  speak  of  the  leaves  of 
the  plant  we  usually  have  in  mind  the  foliage  leaves  or  green 
chlorophyll  leaves. 

Under  the  influence  of  sunlight  the  chloroplasts  are  able  to 
rearrange  the  elements  in  carbon  dioxide  and  water,  which  are; 
looked  upon  as  inorganic  substances,  into  starch  or  related  com- 
pounds which  are  of  an  organic  nature.  This  process  is  known 
as  carbon  dioxide  assimilation,  or  PHOTOSYNTHESIS,  which  latter 
term  means  the  building  up  of  a  compound  under  the  influence  of 
light.  In  this  process,  which  is  sometimes  expressed  by  the  fol- 
lowing formula,  oxygen  is  given  off : 

6C02  +  5H20  =.  C6H1005  +  602 

Carbon  dioxide        Water  Starch  Oxygen 

The  importance  of  this  function  can  be  best  appreciated  by 
bearing  in  mind  that  all  of  the  organic  products  built  up  by  the 
plant  are  derived  almost  entirely  from  the  carbon  dioxide  of  the 
air  which  is  taken  in  through  the  leaves.  (Consult  also  pages 

I57-I59-) 

Transpiration  and  respiration  are  also  functions  of  the  leaf. 
TRANSPIRATION  is  the  giving  off  of  water  (through  water-pores), 
or  watery  vapor  (through  the  stomata),  which  has  been  absorbed 
by  the  root-hairs  and  transported  through  the  tissues  of  the  root, 
stem  and  leaf ;  the  process  of  breathing,  or  RESPIRATION,  consists 
in  the  taking  in  of  oxygen  and  giving  off  of  carbon  dioxide,  the 
exchange  being  just  the  reverse  of  what  it  is  in  photosynthesis. 
These  several  functions  are,  however,  not  confined  to  the  leaf 
alone,  but  are  carried  on  by  all  the  green  parts  of  the  plant. 

PHYSIOLOGICAL  EXPERIMENTS. — The  leaf  is  undoubtedly  the 
most  active  part  of  the  plant  from  the  physiological  point  of  view. 
Some  of  its  activities  can  be  demonstrated  by  comparatively  sim- 
ple means. 

For  instance,  it  can  readily  be  shown,  that  leaves  or  rather 
chloroplastids  form  starch  when  exposed  to  sunlight  but  that  no 
starch  is  formed  when  the  light  is  not  admitted,  by  a  simple  con- 
trivance called  a  leaf  shield.  This  is  a  device  by  which  a  thin 
piece  of  glass  can  be  clamped  against  the  leaf.  Over  a  portion  of 
this  glass  a  piece  of  tinfoil  may  be  pasted,  thereby  shutting  off 
the  light  from  the  underlying  area.  The  procedure  consists  as 


MORPHOLOGY  OF  HIGHER  PLANTS.  351 

follows :  On  the  day  previous  to  the  demonstration  of  the  experi- 
ment the  leaf  shield  is  clamped  on  the  leaf.  On  the  following  day 
the  leaf  is  allowed  to  stand  well  exposed  to  the  sunlight  for 
several  hours.  The  leaf  is  then  removed  from  the  plant,  separated 
from  the  leaf  shield,  and  after  the  chlorophyll  is  extracted  by 
boiling  in  alcohol  it  is  placed  in  weak  iodine  solution,  whereby  the 
entire  part  of  the  leaf  exposed  to  the  light  is  darkened  in  color, 
while  the  area  protected  by  the  tinfoil  remains  unchanged. 

The  phenomenon  of  photosynthesis  whereby  the  leaf  uses 
carbon  dioxide  and  gives  off  oxygen  can  be  demonstrated  by  means 
of  a  photosynthometer.  Ganong  gives  a  detailed  description  of 
its  construction  and  use.  The  underlying  principle  is  that  a 
known  volume  of  leaf  material  is  supplied  with  a  known  volume 
of  carbon  dioxide.  After  submitting  the  leaf  to  the  sunlight  a 
test  is  made  of.  the  proportion  o-f  carbon  dioxide  and  oxygen  in  the 
graduated  tube,  from  which  the  activity  of  the  leaf  may  be 
accurately  deduced. 

The  process  of  transpiration  in  leaves  can  also  be  readily 
shown.  The  mere  fact  of  transpiration  can  be  shown  by  inserting 
the  leaves  of  a  plant  into  a  bell-jar  which  has  at  its  base  a  sheet 
of  rubber  or  other  suitable  material  stretched  over  the  opening 
with  just  sufficient  aperture  to  admit  the  stem.  The  root  being 
outside  of  the  bell- jar  can  be  kept  moist  and  as  transpiration 
takes  place  the  moisture  condenses  on  the  inside  of  the  glass. 

By  means  of  an  arm  balance  and  devices  for  measuring  the 
water  supplied  the  plant,  together  with  some  covering  to  prevent 
evaporation  from  the  surface  of  the  soil,  rather  accurate  deter- 
minations can  be  made  of  the  quantities  of  water  given  off  by  the 
plant  and  calculations  made  for  each  square  unit  of  leaf  surface. 

The  potometer  is  another  ingenious  simple  contrivance  which 
measures  most  accurately  the  amount  of  water  transpired.  It 
consists  of  a  horizontally  placed  graduated  tube  which  ends  in  a 
short  vertical  portion  into  which  a  stem  bearing  leaves  can  be 
tightly  inserted  after  the  instrument  is  filled  with  water.  By 
means  of  a  reservoir  at  the  side  and  a  stop-cock  more  water  can 
be  admitted  as  needed.  Accurate  readings  over  short  periods  of 
time  are  facilitated  by  admitting  a  small  bubble  of  air  as  an  index 
and  observing  the  time  of  its  passage  along  the  graduated  tube. 

(Consult  Ganong:    Plant  Physiology.) 


352 


A  TEXT-BOOK  OF  BOTANY. 


Leaf  Venation. — The  foliage  leaves  of  higher  plants  are 
traversed  by  vascular  bundles,  which  enter  the  blade  through  the 
petiole  and  diverge  at  the  base,  or,  as  in  the  case  of  Dicotyledons, 
branch  in  various  ways ;  and  it  will  be  seen  that  the  form  of  the 
leaves  corresponds  to  the  distribution  of  the  bundles.  These 
bundles  are  known  as  veins  or  nerves,  and  they  have  two  func- 
tions, namely,  (i)  that  of  a  mechanical  support,  and  (2)  that  of 
carrying  nutritive  materials  to  and  from  the  leaves. 

The  mode  of  venation  in  Monocotyledons  and  Dicotyledons 
differs  somewhat,  but  it  will  be  found  that  in  a  number  of  instances 


FIG.  202.  Leaf  venation:  A,  parallel-veined  leaf  of  Solomon's  seal  (Smilacina  race- 
mosa);  B,  pinnately-reticulate  leaf  of  chestnut;  C,  palmately-veined  leaf  of  Menispermum 
canadense. 

the  venation  of  leaves  of  plants  belonging  to  one  of  these  great 
groups  will  resemble  that  of  the  leaves  of  certain  plants  in  the 
other  group.  However,  there  are  certain  general  types  belonging 
to  each  group  (Fig.  202). 

VENATION  IN  MONOCOTYLEDONS. — An  examination  of  the 
leaf  of  lily-of- the- valley  shows  that  the  primary  veins  run  more 
or  less  parallel  to  the  apex  with  short  though  distinct  anastomoses. 
Such  a  leaf  is  said  to  be  PARALLEL-VEINED  or  NERVED.  It  will 
moreover  be  noticed  that. the  distribution  of  the  veins  in  this 
manner  produces  a  lamina  with  an  even,  or  entire  margin,  and 


MORPHOLOGY  OF  HIGHER  PLANTS.  353 

such  a  system  of  venation  is  known  as  a  closed  system  of  venation 
(Fig.  202,  A).  The  leaves  of  Veratrum  and  Zea  Mays  furnish 
other  examples  of  parallel-nerved  leaves. 

In  palms  the  venation  is  somewhat  different.  The  veins, 
instead  of  converging  toward  the  apex  as  they  do  in  the  more  or 
less  lanceolate  leaf  of  lily-of -the- valley,  radiate  from  the  base 
to  the  margin  of  the  more  or  less  round  leaf,  and  a  leaf  of  this 
type  is  said  to  be  PALMI-NERVED. 

There  is  still  a  third  type  of  venation  in  Monocotyledons.  In 
this  instance  one  principal  vein  runs  from  the  base  to  the  apex 
of  the  leaf,  and  from  this  branches  run  parallel  to  the  margin. 
The  banana  furnishes  an  example  of  this  type,  and  is  said  to  be 

PINNI-NERVED. 

VENATION  IN  DICOTYLEDONS. — Here  the  veins  are  character- 
ized by  their  habit  of  repeatedly  branching  and  anastomosing, 
whatever  the  general  type  of  venation  may  be,  and  thus  form  a 
net-work  or  reticulum,  hence  the  leaves  are  said  to  be  RETICULATE 
or  NETTED-VEINED.  The  principal  types  are  as  follows :  A  chest- 
nut or  chinquapin  leaf  (Fig.  202)  furnishes  a  good  illustration 
of  a  pinnately-reticulate  leaf.  The  principal  vein  which  runs  from 
the  base  to  the  apex  is  called  the  MIDRIB,  while  the  secondary 
veins  which  arise  from  it  and  run  more  or  less  parallel  to  the 
margin  are  sometimes  spoken  of  as  ribs  and  may  be  likened  to  the 
plumes  on  the  shaft  of  a  feather. 

In  other  cases  several  large  veins  arise  at  the  base  and  diverge 
toward  the  margin,  giving  rise  to  PALMATELY-VEINED  leaves,  as 
in  the  leaf  of  maple.  There  are  still  other  types,  as  in  cinnamon, 
which  is  said  to  be  rib-netted,  etc. 

Surface  of  Leaves. — In  addition  to  the  markings  of  leaves 
due  to  veining  there  are  certain  other  characters  which  serve 
to  distinguish  them.  Hairs  are  of  frequent  occurrence  on  leaves, 
being  generally  most  abundant  on  the  dorsal  surface,  especially  the 
veins,  and  various  terms  having  reference  to  the  kinds  of  hairs 
have  been  applied  to  leaves. 

Plant  Hairs. — When  the  surface  of  the  plant  (either  of  stems 

or  leaves)  is  covered  with  short,  fine  hairs,  which  are  not  very 

dense  and  not  matted,  the  surface  is  described  as  PUBESCENT; 

when  the  hairs  are  relatively  long  but  scattered  the  surface  is  said 

23 


354  A  TEXT-BOOK  OF  BOTANY. 

to  be  VILLOUS;  or  when  the  hairs  cover  each  other  in  one  direction 
it  is  described  as  SERICEOUS  or  silky.  When  the  hairs  are  stiff 
though  slender  we  speak  of  a  HIRSUTE  covering;  when  the  hairs 
are  vernate,  thickish  and  stiff,  as  in  Borago,  the  surface  is  spoken 
of  as  being  HISPID.  If  the  hairs  are  bristle-like  the  surface  is 
described  as  STRIGOSE;  or  if  they  are  terminated  by  a  globular, 
glandular  head  (Figs.  100,  124),  as  GLANDULAR.  Again,  when 
the  hairs  are  matted  the  surface  is  described  as  LANATE;  when 
they  are  long  it  is  said  to  be  WOOLLY;  or  when  they  are  short 
and  soft  as  in  Mullein  it  is  said  to  be  TOMENTOSE. 

When  the  hairs  are  hard  and  prickle-like  the  surface  is 
described  as  HISPID  or  STRIGOSE  ;  when  they  are  modified  to  spines 
it  is  said  to  be  SPINOSE  ;  and  when  they  are  hooked  it  is  described 

as   ECHINATE. 

In  still  other  cases  the  epidermal  cells,  particularly  of  leaves, 
are  uneven,  forming  depressions  and  protuberances  which  if 
slight  give  the  surface  the  appearance  described  as  RUGOSE  ;  or  if 
wart-like,  give  the  appearance  known  as  VERRUCOSE.  Further- 
more, the  veins  of  leaves  may  be  quite  prominent,  particularly 
in  the  lower  surface,  and  if  they  are  much  reticulated  in  addition, 
the  surface  is  described  as  RETICULATE. 

Texture  of  Leaves. — Leaves  also  vary  in  texture.  A  thin 
pliable  leaf  is  called  membranous ;  one  which  is  thick  and  leathery, 
coriaceous ;  and  one  which  is  thick  and  fleshy,  succulent,  as  that 
of  the  century  plant  and  Aloe  (Fig.  130). 

Forms  of  Leaves. — The  leaves  of  plants  exhibit  an  almost 
innumerable  variety  of  forms ;  even  on  the  same  plant  there  are  not 
infrequently  several  forms,  as  in  Viola  tricolor  and  sassafras 
(Fig.  203)  ;  even  the  two  margins  of  the  same  leaf  may  vary,  as  in 
Hamamelis  and  Begonia,  when  it  is  known  as  an  inequilateral 
or  asymmetric  leaf.  It  frequently  happens  that-  the  lower  leaves 
on  a  shoot  are  lobed  while  the  upper  ones  are  entire,  or  some  of 
the  leaves  may  be  sessile  and  other  petiolate.  Many  of  the  terms 
used  in  ordinary  language  in  describing  the  forms  of  objects  are 
applied  here  also,  as  linear,  lanceolate,  oblong,  elliptical,  spatulate, 
wedge-shaped,  etc. 

APEX  OF  LEAF. — A  number  of  descriptive  terms  are  employed 
in  describing  the  apex  of  the  lamina,  as  ACUTE,  when  the  form  is 


MORPHOLOGY  OF  HIGHER  PLANTS. 


355 


that  of  an  acute  angle;  OBTUSE,  when  the  angle  is  blunt;  ACUMI- 
NATE, when  the  angle  is  prolonged ;  TRUNCATE,  when  the  end  of 


FIG.  203.  Variation  in  the  form  of  leaves  on  the  same  plant:  A,  B,  C,  Leaves  or 
sassafras;  ,D,  young  castor  oil  plant  showing  cotyledons  (t)  and  variously  lobed  older 
leaves.  1,  lamina;  p,  petiole. 

the  leaf  appears  to  be  cut  off ;  RETUSE,  when  it  is  slightly  notched 
at  the  apex ;  OBCORDATE,  when  the  notch  is  pronounced ;  EMAR- 
GINATE,  when  the  degree  of  notching  is  between  retuse  and 


356  A  TEXT-BOOK  OF  BOTANY. 

obcordate.     Sometimes  the  apex  appears  like  the  continuation  of 
the  midrib,  when  it  is  termed  CUSPIDATE  or  mucronate. 

BASE  OF  LEAF. — Some  of  the  terms  used  in  describing  the  gen- 
eral outline,  as  well  as  the  apex  of  the  leaf,  are  also  applied  to  the 
base,  as  obtuse,  truncate,  cordate,  reniform,  etc.  Other  terms, 
however,  especially  apply  to  the  base,  as  CUNEATE  or  wedge- 
shaped;  CONNATE-PERFOLIATE,  when  opposite  leaves  are  con- 
nected at  the  base  and  surround  the  stem ;  PERFOLIATE,  when  the 
leaf  simply  clasps  the  stem.  In  Monocotyledons  the  base  of  the 
leaf  is  frequently  developed  as  a  closed  or  open  sheath,  some- 
times provided  with  a  membranous  protuberance  between  the 
sheath  and  the  blade,  as  in  the  LIGULE  of  grasses  and  sedges. 

MARGIN  OF  LEAF. — The  leaves  of  many  woody  dicotyledonous 
plants  of  temperate  regions  possess  an  even  margin.  The  others, 
according  to  the  degree  and  character  of  the  incisions  or  inden- 
tations, are  described  as  SERRATE,  when  the  apex  of  the  divisions 
or  teeth  is  sharp  and  directed  forward  like  the  teeth  of  a  saw ; 
DENTATE,  when  the  divisions  project  outward;  CRENATE,  when 
the  teeth  are  more  or  less  rounded ;  REPAND,  when  the  margin  is 
somewhat  wavy ;  SINUATE,  when  the  wavy  character  is  pro- 
nounced ;  LOBED,  when  the  incisions  extend  not  more  than  half- 
way into  the  lamina,  and  the  sinus  (or  hollow)  and  the  lobes  are 
more  or  less  rounded ;  CLEFT,  when  the  incisions  are  still  deeper 
and  the  sinuses  and  lobes  are  somewhat  acute;  and  DIVIDED  (Fig. 
205 ) ,  when  the  incisions  extend  almost  to  the  midrib. 

Compound  Leaves. — The  divisions  of  a  parted  leaf  may 
assume  the  form  of  a  simple  leaf,  when  the  divisions  are  known 
as  LEAFLETS  and  the  whole  as  a  compound  leaf.  The  distinction 
between  a  simple  leaf  and  a  leaflet  is,  that  the  former  has  a  bud  in 
the  axil.  The  difference  between  the  divisions  of  a  simple  leaf 
and  those  of  a  compound  leaf  is  this, — in  the  former  they  never 
become  detached  from  the  petiole  or  midrib,  whereas  in  the  com- 
pound leaf  they  are  articulated  and  drop  off  individually.  Com- 
pound leaves  may  be  divided  into  PiNNATELY-compound  (Fig.  204) 
or  pALMATELY-compound  (Fig.  210,  E),  this  distinction  depend- 
ing upon  whether  the  leaflets  are  arranged  pinnately  or  palmately. 
A  number  of  forms  of  pinnately-compound  leaves  are  recognized. 
When  the  leaflets  are  all  lateral  (Fig.  207)  the  leaf  is  said  to  be 


MORPHOLOGY  OF  HIGHER  PLANTS. 


357 


PARI-PINNATE;  when  there  is  an  odd  or  terminal  leaflet  as  in 
the  locust  (Fig.  204)  the  leaf  is  IMPARI-PINNATE;  when  the  midrib 


FIG.  204.  Leaves  having  different  forms  of  stipules  (s) :  A,  bud-scale  stipules  of  Lirio- 
dendron  Tulipifera;  B,  thorny  stipules  and  odd-pinnate  compound  leaf  of  the  locust  tree 
(Robinia  Pseud-acacia);  C,  adnate  stipules  of  rose;  D,  filiform  stipules  of  the  pear;  E,  fringed 
clasping  stipules  (ocrea)  characteristic  of  all  of  the  Polygonums;  F,  adnate  stipules  of  clover. 

is  prolonged  into  a  tendril  as  in  the  garden-pea    (Pisum)   the 
leaf  is  said  to  be  CIRRHIFEROUS-PINNATE. 

Movements  of  Leaves. — The  leaves  as  well  as  other  organs 
of  plants  exhibit  a  variety  of  movements  or  curvatures  in  response 


358 


A  TEXT-BOOK  OF  BOTANY. 


to  stimuli  of  different  kinds,  and  are  said  to  possess  the  property 
of  irritability.  Movements  of  organs  are  of  two  general  classes : 
(i)  Those  due  to  stimuli  which  originate  in  the  plant  and  (2) 
those  due  to  the  influence  of  external  factors.  To  the  former  class 


FlG.  205.  Limnophila  heterophylla,  a  marsh-plant  belonging  to  the  Scrophulariacese 
and  growing  in  tropical  Asia.  The  submerged  or  water  leaves,  below,  are  much  divided  and 
arranged  in  apparent  whorls;  while  the  leaves  at  the  end  of  the  shoot  above  water  are  entire 
and  arranged  in  decussate  dimerous  whorls.  In  between  occur  transition  forms,  which  are 
divided  and  variously  lobed  and  arranged  in  decussate  whorls. — After  Goebel. 

belong  all  those  movements  which  occur  during  the  course  of 
development  from  the  young  to  the  mature  stage.  These  are 
known  as  growth  movements  or  NUTATION.  They  are  especially 
noticeable  in  tips  of  growing  branches,  which  instead  of  growing 


MORPHOLOGY  OF  HIGHER  PLANTS.  359 


FIG.  206.  i,  Leaf,  fruits  and  flowers  of  Anemone  Pulsatilla.  2,  Leaf,  flower  and  fruit 
of  Anemone  pratensis.  The  leaves  are  pinnately  divided,  the  divisions  being  further  incised 
or  dissected. 


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in  a  straight  line,  move  either  from  one  side  to  the  other,  or  coil 
or  curve  about  an  imaginary  axis.  This  spiral  movement  is 
known  as  circumnutation  and  is  characteristic  of  twining  stems  and 
tendrils,  as  the  hop  vine  and  tendrils  of  Bryonia  ( Fig.  181 ) .  Nuta- 
tion curvatures  are  due  to  unequal  growth  on  two  sides  of  the 
organ  and  cease  when  there  is  a  cessation  in  growth  or  when 
the  plant  has  reached  maturity. 

The  movements  of  organs  due  to  external  stimuli  are  usually 
in  a  direction  which  shows  a  relation  to  the  direction  of  the  stim- 
ulus, as  those  produced  by  gravity  and  light  (Fig.  207),  and  these 


FIG.  207.  American  senna  (Cassia  marilandica).  The  figure  at  the  left  shows  the  pin- 
nately-compound  leaves  in  the  day  position  when  under  the  influence  of  light,  and  the  one 
to  the  right  the  drooping  position  of  the  leaflets  at  night. 

movements  are  of  use  in  bringing  the  organs  into  more  favorable 
positions  for  growth.  Stimuli  of  this  kind  are  spoken  of  as 
orienting  or  TROPIC.  The  compound  leaves  of  a  number  of  plants 
exhibit  in  addition  certain  variable  and  periodic  movements,  which 
have  their  origin  in  a  special  mechanism  known  as  the  PULVINIS. 
The  pulvinis  appears  as  a  swelling  on  the  petiole  and  consists  of 
parenchymatous  tissue  which  is  highly  turgid,  i.e.,  full  of  water. 
Any  stimulus,  such  as  mechanical  shock,  which  causes  a  differ- 
ence in  the  degree  of  turgidity  on  two  sides,  will  result  in  a  move- 
ment of  the  leaves  in  such  plants  as  Mimosa,  Oxalis  and  locust. 
The  leaves  of  Mimosa  pudica,  a  common  cultivated  sensitive  plant, 
show  a  very  rapid  response  to  such  stimuli,  the  leaflets  folding 


MORPHOLOGY  OF  HIGHER  PLANTS. 


361 


together  and  the  petiole  and  petiolules  drooping.  In  other  cases 
there  is  a  change  in  the  position  of  the  leaves  following  the  alter- 
nations of  day  and  night.  During  the  day  the  leaflets  are  spread 
out  freely,  but  at  night  or  in  darkness  they  droop  and  fold 
together.  These  are  spoken  of  as  nyctinastic  (nyctitropic)  or 
"  sleep  movements,"  and  are  exhibited  by  a  number  of  leguminous 
plants,  as  clover,  bean,  Cassia  (Fig.  207),  and  by  wood-sorrel 
(Oxalis  Acetosella)  and  various  cultivated  species  of  Oxalis.  The 
leaves  of  Oxalis  as  well  as  of  some  other  plants  fold  together 


II 


FIG.  208.  So-called  carnivorous  plants.  I,  the  pitcher  plant  (Sarracenia  Purpurea) 
showing  the  modified  pitcher-like  leaves  (A)  with  inflated  portion  which  narrows  into  the 
petiole,  and  a  terminal,  more  or  less  spreading  winged  portion;  and  a  flower  and  flower-bud 
(B).  II,  three  species  of  sundew:  A,  Drosera  rotundifolia;  B,  D.  intermedia;  C,  D. 
longifolia. — I,  after  Gray;  II,  after  Drude. 

under  the  influence  of  intense  light  as  well  as  at  night  or  when 
the  amount  of  light  is  reduced.  Of  special  interest  also  are  the 
lateral  leaflets  of  Desmodium  gyrans  (telegraph  plant)  which 
describe  curvatures  at  more  or  less  regular  intervals  day  and 
night  when  the  temperature  is  favorable.  The  leaves  of  the  sundew 
(Drosera)  are  remarkable  for  their  sensitiveness  to  touch.  The 
upper  surface  and  margin  are  provided  with  peculiar  hairs  or 


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tentacles  (Fig.  208,  //)  which  when  touched,  as  by  an  insect, 
gradually  curve  inward.  Not  only  this',  the  stimulus  may  be  trans- 
mitted to  other  tentacles  and  sometimes  even  the  blade  itself  may 


FIG.  209.  Flowering  plant  of  Venus's  Flytrap  (Dioneea  muscipula)  of  North  Carolina, 
showing  the  sensitive  armed  leaves  both  open  and  closed,  in  one  of  which  an  insect  has  been 
imprisoned. — Drawn  from  nature  by  Florence  Newton. 

roll  inward  to  some  extent,  thus  entrapping  small  insects  which 
serve  as  food  to  the  plant.  The  leaves  of  a  related  plant  Dioncea 
are  even  more  sensitive  and  when  special  hairs  on  the  blade  are 
touched  that  part  of  the  lamina  bearing  these  hairs  closes  with  a 


MORPHOLOGY  OF  HIGHER  PLANTS. 


363 


quick,  trap-like  movement,  imprisoning  its  insect  prey  (Fig.  209). 
Phyllotaxy,  or  phyllotaxis,  is  the  study  of  the  distribution 
of  leaves  upon  the  stem,  and  of  the  laws  which  govern  it.  If  we 
examine  germinating  plants  of  the  beech,  the  elm,  or  the  oak,  we 
observe  that,  while  the  seed-leaves  are  opposite  to  each  other,  the 
subsequent  leaves  are  arranged  according  to  a  different  order  in 
these  several  plants,  but  in  a  definite  manner  in  each.  In  the  elm, 
the  distribution  of  the  leaves  is  such  that  the  third  leaf  is  directly 
above  the  first;  in  the  beech,  the  fourth  leaf  is  above  the  first,  and 
in  the  oak,  the  sixth  leaf  is  above  the  first.  If  these  leaves  are  con- 
nected in  the  order  of  their  development,  it  will  be  seen  that  they 
describe  a  spiral  in  their  arrangement,  and  it  will  also  be  found 
that  one  or  more  circuits  of  the  stem  are  made  between  the  super- 
imposing leaves.  Furthermore,  it  will  be  found  that  this  arrange- 
ment constitutes  a  mathematical  series  which  may  be  expressed 
in  degrees,  or  the  parts  of  a  circle  that  the  leaves  are  from  each 
other,  this  measure  being  known  as  DIVERGENCE;  or  by  the  number 
of  perpendicular  rows  of  leaves  on  the  stem,  which  are  known  as 

ORTHOSTICHIES. 

The  following  may  serve  to  illustrate  the  terms  used : 


LEAVES. 

DIVERGENCE. 

ORTHOSTICHIES. 

Degrees. 

Parts  of  a  Circle. 

Elm     .                     .... 

1  80 
120 
144 

fc 
i 
t 

Distichous 
Tristichous 
Pentastichous 

Beech  

Oak                  

If  we  examine  the  fractions  used,  we  will  find  that  the  numer- 
ator indicates  the  number  of  turns  around  the  stem  before  encoun- 
tering a  superimposed  leaf,  and  that  the  denominator  indicates 
the  number  of  leaves  found  ;  the  latter  also  expresses  the  number 
of  orthostichies.  On  adding  the  numerators  and  denominators  of 
any  two  successive  fractions,  a  fraction  is  obtained  which  ex- 
presses the  next  highest  arrangement,  as 


In  quite  a  number  of  plants  two  leaves  arise  at  the  nodes,  as 
in  the  Labiatse.    These  are  invariably  situated  opposite  each  other 


364  A  TEXT-BOOK  OF  BOTANY 

on  the  stem,  and  the  successive  pairs  alternate  with  one  another, 
forming  the  decussate  arrangement  of  leaves  (Figs.  180,  i8'i,  184). 

Modified  Leaves. — Leaves  are  variously  modified  and  serve 
for  other  purposes  than  those  already  described.  They  may  be 
fleshy  in  character  and  serve  as  storehouses  for  nutritive  material, 
as  the  seed-leaves  of  the  oak,  or  they  may  serve  for  the  stor- 
age of  water,  as  in  Agave,  Aloe  and  succulents.  In  some  instances, 
particularly  when  situated  near  the  flowers,  they  lose  their  green 
color,  as  in  the  dogwood,  skunk  cabbage  and  others.  In  other 
cases  they  are  modified  so  that  they  serve  as  a  trap  for  insects, 
as  in  Dioncca,  Sarracenia  and  Drosera  (Figs.  208,  209).  The  peti- 
ole may  become  enlarged  and  perform  the  functions  of  the  leaf,  as 
in  the  Acacias  of  Australia ;  or  it  may  become  bladder-like  and 
servers  a  means  for  floating  the  plant,  as  in  the  water  hyacinth. 
The  stipules  may  likewise  be  modified,  becoming  leaf-like,  as  in  the 
pansy  (Fig.  201 )  ;  or  metamorphosed  into  thorns,  as  in  the  locust ; 
or  clasping,  as  in  Polygonum.  In  some  cases  the  leaves  are  very 
much  reduced,  their  functions  being  performed  by  the  stem,  as  in 
Cactacese,  or  even  by  the  roots,  as  in  some  orchids  which  have 
assimilating  roots. 

Prefoliation  or  vernation  is  the  disposition  of  leaves  in  the 
bud.  The  terms  used  to  describe  the  folding  of  the  leaves  in  the 
bud  are  derived  from  an  examination  of  transverse  sections  of 
the  bud.  The  following  are  some  of  the  terms  which  are  em- 
ployed: CONDUPLICATE,  when  the  lamina  of  the  leaf  is  folded 
lengthwise  along  the  midrib  so  that  the  two  halves  of  the  upper 
surface  lie  together,  as  in  the  Magnoliaceoc ;  PLICATE  or  plaited, 
when  the  lamina  is  folded  along  the  veins,  like  a  closed  fan,  as  in 
the  maples ;  CONVOLUTE,  when  rolled  lengthwise  and  forming  a 
coil  in  cross  section,  as  in  the  Rosacece;  INVOLUTE,  when  both  mar- 
gins are  inrolled  lengthwise  on  the  upper  surface,  as  in  the  violets  ; 
REVOLUTE,  when  both  margins  are  inrolled  lengthwise  on  the  lower 
surface,  as  in  Azalea. 

In  addition,  there  are  several  terms  used  which  are  derived 
from  the  appearance  of  the  bud,  as  RECLINATE  or  inflexed,  when 
the  upper  part  is  -bent  on  the  lower,  as  in  Liriodendron ;  and 
CIRCINATE,  when  the  upper  part  is  coiled  on  the  lower  so  that  the 
tip  of  the  leaf  is  in  the  center  of  the  coil,  as  in  the  ferns. 


MORPHOLOGY  OF  HIGHER  PLANTS.  365 

THE  INNER  STRUCTURE' OF  THE  LEAF 

In  all  green  leaves  the  typical  structure  is  as  follows :  A  cuticle 
covers  the  outer  cell-wall  of  the  epidermis,  while  the  epidermis 
itself  shows  much  of  the  same  modifications  as  exist  in  the  stem ; 
frequently  the  lumen  of  the  cells  of  the  epidermis  is  wider  on  the 


FIG.  210.  Group  of  transplanted  wild  plants  showing  variation  in  form  of  leaves. 
A,  Cinnamon  fern  (Osmunda  cinnamomea)  showing  sporophylls  (fertile  leaves)  and  a  cluster 
of  pinnatifid  sterile  leaves,  the  pinnae  being  linear-lanceolate  and  deeply  pinnatifid;  B, 
wild  ginger  (Asarum  canadense)  showing  basal,  reniform,  long-petiolate  leaves  with  cordate 
base  and  slightly  pointed  apex;  C,  young  hickory  (Hicoria  ovata)  showing  the  odd-pinnate 
(impiri  pinnate),  5-  to  7-foliate  leaves;  D,  ternate,  decompound  leaf  of  Virginia  grape  fern 
(Botrychium  virginianum) ;  E,  digitately  compound  leaves  of  cinquefoil  (Potentilla). 

ventral  face  than  on  the  dorsal.  Hairs  abound  on  the  leaves  in 
many  plants,  and  stomata  are  especially  frequent  on  the  dorsal 
surface.  The  upper  epidermis  may  further  be  characterized  by 
the  presence  of  water-pores,  the  origin  and  function  of  which  have 
already  been  described  (Fig.  147). 


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The  green  chlorophyll-bearing  tissue  is  called  CHLORENCHYMA 
(frequently  spoken  of  as  mesophyll),  and  is  frequently  differen- 
tiated into  a  ventral  PALISADE  TISSUE,  composed  of  long  cells 
which  are  placed  vertically  to  those  of  the  epidermis;  and  a 
DORSAL  PNEUMATIC  TISSUE,  made  up  of  irregularly  branched  or 
lobed  cells  with  very  large  intercellular  spaces.  Secretory  cells  or 
receptacles  occur  in  the  chloTenchyma  of  many  plants  and  corre- 
spond with  those  found  in  the  cortex  of  the  stem.  When  the 
palisade  tissue  occurs  on  both  faces  of  the  leaf  blade  with  the  pneu- 


ST- 


FIG.  211.  Transverse  section  of  midrib  of  leaf  of  stramonium:  EU,  upper  epidermis; 
CO,  collenchyma;  PA,  palisade  cells;  O,  layer  of  cells  containing  rosette  aggregates  of 
calcium  oxalate;  M,  loose  mesophyll;  EL,  lower  epidermis;  OP,  prisms  of  calcium  oxalate; 
OS,  sphenoidal  micro-crystals  of  calcium  oxalate;  ST,  stoma;  T,  tracheae;  SU,  leptome  or 
sieve  on  upper  side  of  tracheae  or  vessels;  SL,  sieve  on  lower  side  of  tracheae,  this  arrange- 
ment of  leptome  or  sieve  and  tracheas  forming  bicollateral  fibrovascular  bundles. 

matic  tissue  in  the  center,  the  leaf  is  called  "  unifacial  "  or  "  iso- 
lateral  "  (Figs.  211,  215)  ;  otherwise  the  leaf  is  said  to  be  "  bi- 
facial "  or  "  dorsiventral,"  i.e.,  with  two  distinct  surfaces. 

Mechanical  tissues,  as  collenchyma  and  stereome,  are  frequent 
and  these  accompany  the  veins  as  hypodermal  strands,  being  best 
developed  usually  on  the  dorsal  face  of  the  latter,  as  underneath 
the  leptome.  The  mestome-strands  of  the  leaf  blade  generally 
lie  in  a  single  plane.  They  are  collateral  and  have  the  leptome 
situated  towards  the  dorsal  face.  They  are  nearly  always  sur- 


MORPHOLOGY  OF  HIGHER  PLANTS. 


367 


rounded  by  thin-walled  PAREXCHYMA-SHEATHS,  or  as  in  several 
grasses  and  sedges  by  thick-walled  mestome-sheaths.  In  some 
plants  of  various  families,  the  midrib  is  not  only  stronger  devel- 


FIG.  212.  Study  of  the  stomata  on  leaves  of  Beta  vulgaris:  A  and  B,  surface  sections 
of  the  leaf,  and  C  and  D,  transverse  sections  of  the  stomata.  In  A  and  C,  the  stomata 
are  shown  with  the  guard  cells  (s)  distended  and  the  pore  (sp)  open  to  allow  the  passage  of 
vapors  and  gases.  B  and  D,  showing  the  pore  or  opening  closed  due  to  the  plasmolysis 
of  the  contents  of  the  guard  cells,  the  internal  pressure  or  tension  having  been  relieved. 
e,  epidermal  cells;  a,  large  cavity  or  intercellular  space  beneath  stomata;  and  m,  loose 
mesophyll  cells  with  chloroplasts. — After  Frank. 

oped  than  the  lateral  veins,  but  it  may  be  composed  of  several, 
instead  of  only  one,  mestome-strand,  sometimes  representing  a 
true  stele. 


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The  petiole  generally  shows  the  structure  of  the  midrib  as  far 
as  concerns  the  mestome-strands,  but  possesses  furthermore  a 
more  or  less  strongly  developed  parenchyma,  the  cells  of  which 


FIG.  213.  Development  of  stomata  on  leaves  of  Sedum  purpurascens:  in  A  very 
early  stages  of  growth,  and  B  nearly  completed  stoma.  In  B  are  shown  a  stoma  with  two 
guard  cells,  three  neighboring  cells  and  two  of  the  epidermal  cells  (e) ;  the  numbers  in  B 
correspond  to  those  in  A  and  show  the  origin  of  the  several  cells  from  the  division  of  a  single 
epidermal  cell. — After  Sachs. 

are  colorless,  thin-walled  and  which  may  often  be  traced  to  the 
leaf-blade  itself,  where  it  surrounds  the  stronger  veins,  causing 


FIG.  214.  Transverse  section  through  a  stomata  showing  how  by  a  slight  difference 
in  the  tension  the  pore  is  either  opened  or  closed;  the  dark  lines  show  contour  of  cells 
when  open,  the  light  lines  show  when  they  are  closed. — After  Schwendener  (See  Haberlandt, 
Physiologische  Pflanzenanatomie). 

them  to  project  as  ribs  and  to  be  much  thicker  in  cross-section 
than  the  adjoining  chlorenchyma. 

From   a   histological   point   of   view   the   leaf    structure    of 


MORPHOLOGY  OF  HIGHER  PLANTS. 


369 


Dicotyledons  resembles  very  closely  that  of  the  Monocotyledons, 
except  that  in  the  latter  the  palisade-cells  often  radiate  towards 
the  center  of  the  mestome-strands.     There  are,  however,  many 
instances  of  a  similar  development  in  the  leaves  of  Dicotyledons. 
Abnormal  structures  are  common  in  leaves,  especially  in  such 


FlG.  215.  Transverse  section  of  leaf  of  Phytolacca  decandra  showing  upper  epidermis 
(ue),  palisade  cells  (p),  raphides  (r),  spiral  tracheae  (v),  loose  mesophyll  (m)  with  large 
intercellular  spaces,  and  lower  epidermis  (le)  with  a  stoma. 

as  are  not  held  in  a  horizontal  position,  but  vertical,  as  those  of 
Eucalyptus,  the  Irideae,  etc. 

The  Epidermis  forms  the  surface  of  the  leaf  and  may  con- 
sist of  one  or  more  layers  of  cells.    The  outer  walls  are  cutinized, 
and  when  nearly  smooth  the  leaf  is  said  to  be  GLABROUS.     They 
may  be  covered  or  whitened  with  a  bloom,  as  in  magnolia,  when 
24 


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A  TEXT-BOOK  OF  BOTANY. 


the  leaves  are  spoken  of  as  GLAUCOUS.     In  other  cases  the  outer 
walls  of  the  epidermal  cells  are  modified  to  hairs  (Figs.  100,  124, 

125,  I4&-I55)- 

ANATOMICAL  DIFFERENCES  IN  LEAVES. — The  walls  of  the 
epidermal  cells,  although  usually  isodiametric,  are  often  very 
zig-zag  in  outline.  In  size,  the  upper  epidermal  cells  are  usually 
larger  in  a  given  species  than  those  of  the  lower  surface,  and 
sometimes  are  rather  linear,  resembling  a  palisade  layer.  The 


FIG.  216.  A,  transverse  section  of  leaf  of  Lobelia  inflata  showing  the  large  irregular 
epidermal  cells  (e),  palisade  cells  (p),  trachea  (t),  loose  parenchyma  (m),  and  lower  epider- 
mis (i).  B,  transverse  section  of  leaf  of  Matico  showing  oil-secretion  reservoir  (o),  upper 
epidermis  (e),  lower  epidermis  (1),  with  non-glandular  hairs  (h),  palisade  layers  (p),  loose 
mesophyll  (m). 

cuticle  may  be  thin  or  leathery  and  tough,  and  sometimes  is  pro- 
vided with  minute  ridges  or  crests,  especially  on  the  under  sur- 
face, thereby  giving  a  dull  appearance  to  the  leaf.  Many  leaves, 
too,  excrete  wax  on  the  surface  and  consequently  have  a  glaucous 
or  hoary  appearance,  notably  some  of  the  poppies,  the  common 
jewel-weed  and  many  others.  Other  modifications  may  have 
to  do  with  the  gelatinization  of  the  epidermis  of  the  leaf,  assisting 
in  the  storage  of  water,  as  in  the  leaves  of  the  violets.  The 
differentiation  in  forms  of  calcium  oxalate  crystals  is  also  im- 


MORPHOLOGY  OF  HIGHER  PLANTS.  371 

portant  in  distinguishing  plants  that  resemble  each  other.  The 
size  and  number  of  stomata  as  well  as  their  distribution  and 
arrangement  with  respect  to  each  other  varies  in  different  plants. 
For  example,  in  certain  saprophytic  or  submerged  plants  the  num- 
ber of  stomata  is  greatly  or  even  completely  reduced,  and  when  pres- 
ent are  quite  functionless.  Sometimes  the  stomata  are  depressed 


FIG.  217.  Transverse  section  of  leaf  of  Matico  near  two  veins;  showing  the  upper 
epidermis  of  several  layers  (e),  two  layers  of  palisade  cells  (p),  tracheae  (t),  sieve  (s),  collen- 
chyma  (c),  loose  parenchyma  containing  crystals  of  calcium  oxalate  (ca),  and  non-glandular 
hairs  (h). 

below  the  surface  of  the  leaf,  this  being  true  in  plants  occurring 
in  dry  or  cold  districts,  and  is  distinctly  characteristic  of  many 
Coniferse. 

There  is  a  marked  difference  in  the  arrangement  of  the  pali- 
sade tissues,  the  following  types  being  distinguished :  i.  In  bifacial 


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A  TEXT-BOOK  OF  BOTANY. 


N 


FIG.  218.  Digitalis  leaves:  A,  transverse  section  near  one  of  the  veins  showing  the 
separated  or  extra-epidermal  layer  occurring  on  the  lower  surface  (S)  with  two  non-glandular 
hairs  (N)  and  glandular  hair  (G),  epidermal  layer  (E),  lower  epidermis  (LE),  chlorophyll 
layer  (M),  upper  epidermis  (UE),  and  tracheae  (T).  B,  transverse  section  of  portion  of 
leaf  showing  the  separated  or  additional  epidermal  layer;  c,  collenchyma. 

or  dorsiventral  leaves  the  palisade  cells  are  distributed  only  below 
the  upper  epidermal  layer  (Figs.  211,  215).     2.  In  unifacial  or 


MORPHOLOGY  OF  HIGHER  PLANTS.  373 

isolateral  leaves  the  palisade  cells  occur  beneath  the  epidermal 
layers  of  both  leaf  surfaces,  as  in  senna.  3.  In  some  leaves,  as 
in  Eucalyptus,  the  entire  parenchyma  is  made  up  of  palisade 
cells.  4.  In  a  few  leaves  there  is  no  differentiation  of  a  palisade 
layer,  and  these  are  sometimes  referred  to  as  centric  leaves.  The 
palisade  cells  may  contain  not  only  chloroplastids  but  crystals  of 
calcium  oxalate  (Fig.  215),  tannin-inclusions  (Fig.  114),  etc. 
Distributed  among  the  palisade  cells  may  be  the  oil-secretion 
reservoirs  (Fig.  216,  B).  Furthermore,  the  palisade  cells  may 
be  of  equal  length  or  the  stratification  may  be  quite  uneven  and 
irregular.  In  shape  they  may  vary  from  long,  narrow  cells  to 
short,  broad  cells.  In  some  special  instances  they  are  narrowed 
at  the  lower  end  in  the  form  of  a  blunt  cone  forming  the  so-called 
"  funnel  cells,"  which  are  especially  characteristic  of  plants  in- 
habiting moist  localities.  There  is  still  another  common  form 
known  as  arm-palisade  parenchyma,  in  which  the  cells  are  branch- 
ing and  connected  with  each  other  by  means  of  the  branches. 
Tissues  of  this  type  occur  in  the  Equisetacese,  Filices,  Coniferse, 
Graminese,  and  in  a  number  of  Dicotyledons,  such  as  Aconitum, 
Adonis,  Anemone,  Caltha,  Clematis,  Delphinium,  Nigella,  Pseonia, 
and  Trollius  in  the  Ranunculacese ;  Sambucus  and  Viburnum  in 
the  Capri foliacese;  Lysimachia  and  Trientalis  in  the  Primulacese. 
The  spongy  tissue  or  dorsal  pneumatic  tissue  shows  consider- 
able variation  in  the  arrangement  and  shape  of  the  cells.  In  some 
leaves  the  cells  are  arranged  in  strata  or  layers,  while  in  others 
they  are  more  or  less  irregular.  The  cells  may  be  spherical  or 
provided  with  a  number  of  arms,  the  latter  developing  parallel 
to  the  surface  of  the  leaf  or  radiating  in  any  direction,  thus  caus- 
ing a  variation  in  the  nature  and  size  of  the  intercellular  spaces. 
In  some  instances  there  are  included  in  the  mesophyll  certain 
mechanical  cells,  of  which  the  simplest  are  like  ordinary  stone 
cells.  They  may  be  more  or  less  elongated  or  branched  or  even 
quite  fibrous,  and  are  known  as  SPICULAR  CELLS.  The  latter  are 
sometimes  quite  prominent  when  they  traverse  the  leaf  in  a  verti- 
cal direction,  giving  rise  to  translucent  spots.  Spicular  cells  have 
been  found  in  the  mesophyll  of  quite  a  number  of  families.  They 
are  quite  characteristic,  although  absolutely  not  constant,  in  the 
^genuine  tea  leaf  (Thea  sinensis). 


374  A  TEXT-BOOK  OF  BOTANY. 

IV.  OUTER  MORPHOLOGY  OF  THE  FLOWER. 

It  is  well  known  if  the  stem  of  a  plant,  as  the  carnation,  rose, 
geranium,  etc.,  be  cut  into  pieces  so  that  each  portion  has  at  least 
one  node  and  placed  under  suitable  conditions  for  growth,  roots 
will  arise  from  the  nodes  that  are  in  the  ground  and  a  new  plant 
will  be  developed.  The  same  result  can  be  achieved  if  plants  like 
Ficus,  growing  in  a  greenhouse,  have  placed  around  the  nodes  near 
the  tip  of  the  branches  a  clump  of  sphagnum,  and  if  the  latter 
be  kept  moist  roots  will  arise  from  the  joints.  This  method  of 
increasing  the  number  of  individual  plants,  while  it  is  limited  to 
certain  perennials  and  cannot  be  followed  with  annuals  or  bien- 
nials, is  frequently  resorted  to  by  horticulturists,  and  is  known 
as  vegetative  propagation.  The  production  of  independent  plants 
in  this  manner  is  dependent  upon  the  property  of  the  meristematic 
cells  in  the  pericycle  of  the  stem  to  produce  the  meristems  that 
give  rise  to  the  tissues  of  the  root.  As  this  process  of  propagation 
for  plants  growing  in  temperate  regions  and  in  cold  climates  would 
be  more  or  less  uncertain  for  the  perpetuation  of  the  species,  it 
is  fortunate  that  in  Nature  safer  methods  of  reproduction  are 
followed,  depending  upon  the  development  of  flowers  and  the 
production  of  seed.  In  the  latter  there  is  a  young  plant  with  all 
of  the  elements  of  root  and  shoot  contained  therein  and  so  pro- 
tected by  a  seed-coat  that  it  may  withstand  extremes  of  climatic 
conditions,  as  well  as  the  various  hostile  forces  to  which  it  might 
be  subjected. 

THE  FLOWER  is  a  shoot  which  has  undergone  a  metamorphosis 
so  as  to  serve  as  a  means  of  propagating  the  individual.  It  is 
an  unb ranched  and  definite  shoot,  or  an  apex  of  a  shoot.  It 
might  be  termed  a  "  dwarf-branch  "  that  dies  and  drops  off  the 
plant  after  the  maturation  of  the  fruit.  The  most  complete 
flower  has  four  kinds  of  leaves:  sepals,  petals,  stamens,  and 
carpels. 

The  sepals,  usually  green  and  leaf -like,  make  up  the  outer 
spiral  known  as  the  calyx.  The  petals  being  frequently  highly 
colored  form  an  inner  spiral  known  as  the  corolla.  The  stamens 
are  the  polliniferous  organs  of  the  flower,  and  the  carpels  bear 
the  ovules  which  later  develop  into  seeds. 

While  the  flower  is  a  very  complicated   structure  in  many 


MORPHOLOGY  OF  HIGHER  PLANTS.     375 

cases,  the  definition  given  it  by  some  writers  is  very  simple.  It 
is  defined  as  a  branch  which  bears  sporophylls.  As  we  have 
seen,  a  sporophyll  is  a  leaf  which  bears  sporangia.  According  to 
the  definition  given,  the  strobiles  or  cones  of  the  Gymnosperms 
and  certain  Pteridophytes,  as  the  horsetails  and  club  mosses, 
are  entitled  to  rank  as  flowers.  In  Angiosperms  other  leaves  may 
be  present,  and  these  are  known  as  the  FLORAL  LEAVES.  The 
flower,  then,  in  Angiosperms  is  made  up  of  sporophylls  which  are 
essential,  and  floral  leaves  which  may  or  may  not  be  present.  But 
in  speaking  of  the  sporophylls  of  the  flower  in  Angiosperms  it  is 
customary  to  use  terms  which  were  applied  to  them  before  their 
relation  to  the  similar  organs  in  the  Gymnosperms  and  Pterido- 
phytes was  understood.  Thus  the  microsporophylls,  as  already 
pointed  out,  are  known  as  STAMENS,  and  the  megasporophylls  as 
CARPELS. 

For  a  great  many  years  botanists  taught  that  the  stamens  and 
carpels  are  transformed  foliage  leaves, — in  other  words,  that  they 
are  derived  from  foliage  leaves, — but  in  more  recent  years  the 
view  has  been  established  that  they  arise  as  independent  members, 
— are,  in  fact,  as  independent  as  the  foliage  leaves  themselves. 
Various  transformations  or  modifications  may  and  do  occur,  but 
these  are  not  confined  to  the  foliage  leaves  alone,  for  under  cer- 
tain conditions  the  sporophylls  may  assume  the  character  of  floral 
leaves. 

It  is  true  that  in  the  case  of  some  ferns  the  sporophylls  bear 
a  strong  resemblance  to  foliage  leaves,  as  in  Dryopt-eris  Filix-mas 
(Fig.  53),  but  this  does  not  necessarily  prove  that  the  sporophylls 
of  Angiosperms  are  transformed  leaves,  but  only  that  the  further 
back  we  go,  the  less  the  degree  of  differentiation  of  parts  until 
we  reach  the  unicellular  algae. 

The  flowers  of  the  Angiosperms  differ  from  those  of  the 
Gymnosperms  in  that  the  ovules  (megasporangia)  are  enclosed, 
before  pollination,  in  an  ovary  which  has  developed  a  special 
organ — the  stigma — for  the  reception  of  the  pollen  grains  (micro- 
spores),  and  the  floral  envelopes  are  much  more  conspicuous. 

The  several  parts  of  the  flower  are  arranged  more  or  less 
compactly  at  the  terminus  of  an  axis  known  as  the  flower  branch, 
the  special  portion  bearing  these  parts  being  known  as  the  TORUS 


376  A  TEXT-BOOK  OF  BOTANY. 

(sometimes  spoken  of  as  the  receptacle),  and  that  portion  below 
the  flower  proper  as  the  flower  stalk  (Fig.  78,  PE).  The  carpel 
or  carpels  occupy  the  terminal  portion  of  the  branch,  while  the 
stamens  and  floral  leaves  occur  in  circles  or  whorls  below. 

Pistil. — There  may  be  only  one  carpel  present  in  a  flower, 
or  there  may  be  more.  In  the  latter  case  the  carpels  may  remain 
distinct  or  they  may  be  united,  but,  whatever  the  number  or  the 
degree  of  union,  it  is  the  carpel  or  carpels  which  constitute  the 
closed  structure  known  as  the  pistil.  The  pistil  is  usually  differ- 
entiated into  three  quite  distinct  regions:  (i)  A  lower  bulbous 
portion  which  contains  the  ovules,  known  as  the  OVARY;  (2)  a 
neck-like  portion  known  as  the  STYLE;  and  (3)  at  the  top  of 
the  style  a  specialized  portion  which  receives  the  pollen,  known 
as  the  STIGMA  (Figs.  78  and  219).  When  the  pistil  is  made  up 
of  a  single  carpel  it  is  said  to  be  SIMPLE,  and  when  composed 
of  more  than  one  carpel  it  is  called  COMPOUND. 

The  carpels  in  the  compound  pistil  appear  to  be  united  in 
different  ways.  Sometimes  they  appear  to  have  coalesced  or 
grown  together  at  the  margins,  thus  forming  an  ovary  with  but 
one  chamber  or  compartment  ( Fig.  223,  B ) .  In  the  other  cases  the 
carpels  appear  as  though  they  were  incurved  or  folded  together  at 
the  margins  along  the  line  of  union,  thus  forming  septa  or  walls 
which  divide  the  inner  cavity  into  several  compartments  or 
locules  (Fig.  223,  A,  C). 

When  the  carpels  are  not  united  but  remain  separate,  there 
are  as  many  pistils  as  carpels,  as  in  the  flowers  of  buttercup  (Fig. 
223,  D) .  Thus  a  unilocular  ovary  may  belong  to  a  simple  or  com- 
pound pistil. 

GYN^ECIUM. — The  aggregate  of  pistils  in  a  flower  constitutes 
the  gynsecium.  If  the  gynsecium  is  made  up  of  a  number  of  simple 
pistils,  as  in  the  flower  of  buttercup  (Fig.  223,  D),  it  is  said  to  be 
APOCARPOUS.  But  if  the  carpels  are  united  into  one  structure,  then 
the  gynsecium  is  said  to  be  SYNCARPOUS,  as  in  the  orange  flower, 
which  is  in  reality  equivalent  to  a  compound  pistil.  Inasmuch  as 
the  styles  and  stigmas  are  frequently  not  united,  the  expression 
compound  ovary  is  usually  employed.  According  as  the  gynse- 
cium consists  of  one,  two,  three,  or  many  carpels,  it  is  said  to  be 
monocarpellary,  dicarpellary,  tricarpellary,  or  polycarpellary. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


377 


The  pistil  of  the  flower  of  the  pea  is  simple  and  has  an  elon- 
gated ovary,  and  upon  dissecting  the  ovary  and  also  making  a 
transverse  section  of  it,  it  is  observed  that  the  ovules  are  borne 
upon  the  part  which  projects  from  the  concrescent  margins  into  the 
cavity,  this  part  being  known  as  the  PLACENTA,  and  the  united 


J    "  (/  H 

FIG.  219.  Pistils  and  different  kinds  of  stigmas.  A,  simple  (monocarpellary)  pistil 
of  willow  with  lobed  stigma;  B,  compound  pistil  of  Fourcroya  with  head-like  stigma;  C, 
longitudinal  section  through  flower  of  Spondias  with  five  separate  styles  and  stigmas, 
only  three  of  which  are  shown;  D,  flower  of  Peperomia  showing  bristly  stigma;  E,  recurved, 
thread-like  stigmas  of  the  Upas-tree  (Antiaris);  F,  flower  of  a  Canary  grass  showing  the 
two  simple  plumose  stigmas;  G,  pistillate  flower  of  couch  grass  showing  the  two  compound 
plumose  stigmas;  H,  thread-like  stigmas  of  pistillate  inflorescence  of  Euchlawa  one  of 
the  grasses;  J,  tri- parted  stigmas  of  the  pistillate  flower  of  the  castor-oil  plant;  K,  L, 
two  forms  of  stigmas  of  Begonia. — After  Engler. 

margins  of  the  carpel  forming  the  "  inner  "  or  VENTRAL  SUTURE. 
In  the  syncarpous  gynaecium  the  ventral  suture  of  the  carpels  is 
directed  toward  the  axis  of  the  flower ;  in  some  cases  that  portion 
of  the  carpel  corresponding  to  the  midrib  is  very  prominent,  as 
in  the  Papilionatse,  and  has  received  the  name  of  "  outer  "  or 

DORSAL  SUTURE. 

There  are  as  many  locules  in  the  ovary  as  there  are  carpels, 


378  A  TEXT-BOOK  OF  BOTANY. 

and  the  walls  or  partitions  between  the  locules  of  a  syncarpous 
gynaecium  are  known  as  DISSEPIMENTS;  when  three  or  more 
carpels  are  united  the  number  of  dissepiments  corresponds  to  the 
number  of  carpels.  It  sometimes  happens  that  a  partition  or  wall 
is  intruded  from  the  mid-vein  of  the  carpel,  dividing  a  unilocular 
ovary  into  one  that  is  bilocular,  as  in  species  of  Astragalus,  and 
such  a  partition  is  termed  a  FALSE  DISSEPIMENT. 

When  no  other  than  the  true  dissepiments  exist  in  the  syn- 
carpous gynaecium  the  placentas  are  borne  along  the  axis  of  the 
flower  and  are  termed  axial  placentas.  In  the  Caryophyllaceae 
the  ovules  are  borne  upon  a  central  axis,  and  the  dissepiments 
having  been  absorbed  by  the  gynaecium  is  said  to  possess  a  free 
central  placenta.  In  other  cases  the  placentas  grow  backward 
from  the  central  axis  toward  the  mid-vein  of  the  carpel,  carrying 
the  ovules  with  them,  when  they  are  spoken  of  as  parietal  pla- 
centas, as  in  colocynth  fruit  and  watermelon. 

The  STYLE  not  only  varies  in  shape  and  size  but  in  the  manner 
of  attachment  to  the  ovary  (Fig.  219)  ;  it  may  be  very  short,  as  in 
the  clove;  long  and  filiform,  as  in  (Enothera;  club-shaped  (clav- 
ate),  as  in  the  orange;  or  broad  and  petalloid,  as  in  Iris.  It  is 
usually  situated  at  the  summit  of  the  ovary,  when  it  is  said  to  be 
apical  or  terminal ;  it  may,  however,  be  laterally  attached,  as  in 
the  strawberry,  or,  as  in  a  few  instances,  attached  to  the  base  of 
the  ovary.  It  is  usually  smooth,  but  may  be  hairy,  as  in  the  Com- 
positae.  The  styles,  like  the  carpels,  may  be  separate  or  united, 
and  in  the  latter  case  may  have  a  central  canal  connecting  the 
stigma  with  the  ovary,  as  in  the  violets.  While  usually  deciduous, 
the  style  may  be  more  or  less  persistent — forming  a  part  of  the 
fruit — or  even  become  much  elongated,  as  in  the  dandelion. 

The  STIGMA  is  an  essential  part  of  the  pistil  in  that  it  is  the 
germinating  surface  for  the  pollen  grains,  it  being  viscid  and  espe- 
cially adapted  for  this  purpose  (Fig.  219).  The  stigmas  may  be 
separate,  as  in  the  Compositse,  or  they  may  be  united  into  a  more 
or  less  club-shaped  or  globular  head,  consisting  of  as  many  lobes 
as  there  are  stigmas,  as  in  the  poppy.  The  stigma,  while  usually 
solid,  may  have  an  opening,  as  in  the  violets,  which  sometimes  has 
a  lid-like  appendage,  as  in  Viola  tricolor. 

The  OVULES  (Fig.  219),  as  we  have  already  seen,  are  small 


MORPHOLOGY  OF  HIGHER  PLANTS. 


379 


bodies  which  are  borne  on  the  placentas,  and  which,  after  fertiliza- 
tion, develop  into  seeds.  The  number  of  ovules  varies  considerably 
— there  may  be  but  one,  as  in  the  almond,  or  there  may  be  a  large 
number,  as  in  the  watermelon. 

There  are  several  principal  forms  of  ovules  (Fig.  220)  recog- 
nized, of  which  the  following  may  be  mentioned  :  ( i )  ATROPOUS, 
in  which  the  ovule  is  straight  and  erect  on  its  stalk,  as  in  the 
Urticacese;  (2)  AN  ATROPOUS,  in  which  the  ovule  is  bent  over  on  to 
the  stalk  so  as  to  be  in  an  inverted  position,  the  line  of  attachment 
of  the  ovule  and  stalk  being  known  as  the  raphe  (Fig.  230,  n)  ;  (3) 
CAMPYLOTROPOUS,  in  which  the  ovule  is  bent  upon  itself,  as  in 
Stramonium,  this  form  being  less  frequent  than  the  other  two. 
Most  of  the  ovules  of  flowering  plants  are  anatropous. 


FIG.  220.  Three  positions  of  ovules.  A,  atropous;  B,  anatropous;  C,  campylotropous. 
(f)  funiculus  or  stalk;  (c)  chalaza,  or  point  of  union  of  nucellus  and  integuments;  (k)  nucellus 
or  megasporangium;  (em)  embryo-sac  or  megaspore;  (ai)  outer  integument;  (ii)  inner 
integument;  (m)  foramen  or  orifice  for  entrance  of  pollen  tube,  known  as  the  micropyle 
in  the  seed;  (r)  raphe.— After  Prantl. 

Stamen. — As  already  indicated,  the  stamen  consists  of  a 
stalk-like  portion  called  the  FILAMENT,  and  a  specialized  portion 
which  bears  the  sporangia,  called  the  ANTHER  (Fig.  78).  The 
filament  may  be  long  or  short  or  wanting.  It  is  commonly  thread- 
like, but  varies  considerably,  and  is  sometimes  leaf-like. 

The  ANTHER  is  the  essential  part  of  the  stamen  (Fig.  221) 
and  consists  of  two  lobes,  each  of  which  is  composed  of  two  divi- 
sions or  pollen  sacs  (Fig.  79).  These  sacs  contain  the  pollen, 
which  is  commonly  discharged  either  through  a  longitudinal  suture 
or  line  of  dehiscence,  or  through  an  opening  at  the  tip.  The 
anthers  may  be  variously  attached  to  the  filament  (Fig.  221). 
When  they  face  the  axis  of  the  flower  they  are  said  to  be  INTRORSE, 
as  in  the  Violacece,  and  when  they  face  the  perianth  they  are  said 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  221.  Different  types  of  stamens.  Abbreviations:  filament  (f),  pollen  sacs  or 
iheca  (sporangia)  (th),  connective  (c).  A,  stamens  of  a  water  lily  (NymphoBO)  showing 
variation  in  the  stamens  (a-d) ;  B,  theca  near  middle  of  the  stamen  of  Popowia;  C,  anther  of 
another  species  of  Popowia  with  fleshy  connective  and  pollen  sacs  on  either  side;  D,  stamen 
of  Tradescantia  with  transverse  connective;  E,  F,  G,  stamens  of  several  Commelinaceae 
with  broad  connectives;  H,  stamen  of  Salvia  with  peculiar  swinging  connective  and  an 
aborted  pollen  sac  or  staminodium  (std)  at  the  lower  end  and  the  fertile  pollen  sac  above; 
J,  peculiar  elongated  connective  of  Unona;  K,  elongated  connective  of  Humiri;  L,  .andrce- 
cium  of  violet  showing  two  spurred  sessile  stamens;  M,  stamen  of  Columelia  with  sinuous 
confluent  anthers,  broad  connective  and  short  filament;  N,  confluent  transverse  pollen 
sacs  of  Arisarum;  O,  united  pollen  sacs  of  Columbine  showing  small  connective;  P,  spherical 
pollen  sacs  of  C  alia,  with  slightly  developed  connective;  Q,  versatile  anther  and  long,  slen- 
der filament  of  dead  nettle  (Lamium  album) ;  R,  dehiscence  of  anther  of  Solanum  by  means 
of  terminal  pores;  S,  spurred  anther  of  Arbutus  with  terminal  pores;  various  kinds  of  val- 
vular dehiscence,  as  in  Berberis  (T),  Atkerosperma  (U)  and  Persea  (V). — A,  after  Caspary; 
B,  H-R,  U,  V,  after  Baillon;  S,  T,  after  Sachs;  D-G,  after  Schonland. 

to  be  EXTRORSE,  as  in  the  Magnoliacese ;  when  they  lie  horizontally 
on  the  tip  of  the  filament,  so  that  they  swing  as  on  a  pivot,  as  in 
the  tiger  lily,  they  are  said  to  be  VERSATILE  ;  when  they  adhere 


MORPHOLOGY  OF  HIGHER  PLANTS.  381 

longitudinally  to  the  sides  of  the  filament  and  the  dehiscence  is 
marginal,  they  are  said  to  be  INNATE;  when  they  adhere  longi- 
tudinally to  the  filament  and  the  latter  extends  slightly  beyond 
them,  they  are  said  to  be  ADNATE,  in  which  case  they  may  be 
extrorse  or  introrse.  In  some  of  the  Labiatae  the  lobes  of  the 
anther  are  united  at  the  apex  of  the  filament,  but  diverge  from  the 
point  of  attachment  and  are  said  to  be  connate,  coherent,  or 

CONFLUENT. 

The  CONNECTIVE  is  that  portion  of  the  filament  to  which  the 
lobes  of  the  anther  are  attached  or  which  connects  them  (Fig. 
221 );  usually  it  is  not  very  prominent ;  but  in  some  of  the  Labiatae, 
as  in  Salvia,  it  is  rather  broad ;  in  some  of  the  Malvaceae  it  is 
entirely  wanting,  the  two  lobes  being  confluent ;  in  other  cases  it 
may  be  extended  beyond  the  lobes  of  the  anther,  as  in  species  of 
Asarum. 

APPENDAGES  OF  ANTHER. — In  certain  instances  the  anthers 
are  appendaged  (Fig.  221)  :  In  the  violets  there  is  a  triangular 
growth  at  the  apex ;  in  the  oleander  the  apex  is  plumose ;  in  deer 
berry  (V actinium  stamineum)  there  are  two  awn-like  append- 
ages upon  the  back  of  the  anther;  in  the  violets  the  two  stamens 
that  project  into  the  spurred  petal  are  also  spurred  and  secrete  a 
nectar;  in  the  Asclepiadaceae  the  anthers  possess  wing-like  ap- 
pendages, each  sac  or  division  of  which  contains  a  pear-shaped 
coherent  mass  of  pollen  grains  (pollinium). 

When  a  flower  has  but  one  stamen  it  is  termed  MONANDROUS  ; 
and  when  there  are  two,  three,  or  many  stamens,  it  is  said  to  be 
diandrous,  triandrous,  or  polyandrous  (Fig.  223).  The  aggregate 
of  stamens  in  the  flower  is  called  the  ANDRCECIUM.  In  the  Labi- 
atae there  are  four  stamens  arranged  in  a  longer  and  shorter  pair, 
and  the  stamens  are  said  to  be  DIDYNAMOUS  ;  in  the  Cruciferae 
the  flowers  possess  six  stamens,  four  of  which  are  longer  than  the 
other  two,  and  the  stamens  are  described  as  TETRADYNAMOUS  ; 
in  some  plants,  as  in  the  Lobeliaceae,  Papilionatae,  etc.,  the  fila- 
ments cohere,  forming  groups  (Fig.  222)  which  are  termed  mona- 
delphous,  diadelphous,  etc. ;  in  the  flowers  of  the  potato  the 
anthers  lie  close  together  but  are  not  united,  forming  apparently 
a  continuous  ring  or  band  around  the  pistil,  when  they  are  said 
to  be  connivent ;  in  the  tubular  flowers  of  the  Composite  the 


382 


A  TEXT-BOOK  OF  BOTANY. 


anthers  are  united,  forming  a  closed  ring,  and  the  stamens  are 
spoken  of  as  SYNGENESIOUS  (Fig.  222,  A)  ;  in  many  of  the  Cucur- 
bitacea  the  filaments  and  anthers  both  are  confluent ;  in  the  flowers 
of  the  Orchidaceae  the  stamens  are  borne  upon  the  pistil  and  are 
said  to  be  GYNANDROUS. 

Floral  Envelopes. — As  their  name  indicates,  the  floral  en- 
velopes occupy  the  outermost  or  lowest  position  in  the  arrange- 
ment of  the  parts  of  the  flower.  In  the  bud  condition  they  protect 
the  essential  elements,  and  in  the  expanded  flower  are  considered 
to  play  an  important  role  in  securing  pollination  through  the 
visitation  of  insects.  The  floral  envelopes  are  made  up  generally 
of  two  kinds  of  leaves,  petals  and  sepals  (Figs.  224  to  227). 


FIG.  222.  Union  of  stamens.  A,  united  anthers  of  flower  of  Composite;  B,  diadelphous 
stamens  of  Pisum  with  i  free  stamen  and  9  united;  several  types  of  monadelphous 
stamens,  as  in  Erythroxylon  (C),  Melia  Azedarach  (D),  and  common  mallow  (E).— After 
Baillon. 

The  PETALS  form  a  spiral  which  surrounds  the  androecium. 
They  are,  as  a  rule,  quite  bright  and  attractive,  being  frequently 
highly  colored,  as  in  the  rose,  Fuchsia,  violet,  etc.,  and  are  known 
collectively  as  the  COROLLA. 

The  SEPALS  form  the  next  and  lowermost  spiral.  They  are 
usually  green  and  leaf-like,  as  in  the  rose  and  carnation,  and 
together  constitute  the  CALYX.  Sometimes  the  corolla  and  calyx 
are  spoken  of  together  as  the  PERIANTH,  although,  strictly  speak- 
ing, the  term  has  a  more  special  application,  and  is  used  mostly  in 
speaking  of  the  sepals  and  petals  of  monocotyledonous  flowers, 


MORPHOLOGY  OF  HIGHER  PLANTS. 


383 


these  parts  being  much  alike  and  not  distinguishable,  save  in  posi- 
tion, as  in  certain  lilies. 


FIG.  223  Types  of  flowers:  A,  hypogynous  flower  of  flax;  B,  perigynous  flower  of 
cherry,  showing  perianth  tube  with  sepals,  petals  and  stamens  on  its  border;  C,  epigynous 
flower  of  American  sarsaparilla ;  D,  flower  of  buttercup  showing  apocarpous  gynaecium 
and  large  conical  torus;  E,  irregular  (bilateral  or  zygomorphic)  flower  of  aconite 
showing  half  of  helmet-like  sepal  (a),  other  sepals  (b,  c),  long-clawed  nectary  (k)  developed 
from  one  of  the  posterior  petals,  separate  pistils  (f);  P,  corolla  of  Salvia  spread  open  and 
showing  the  two  rudimentary  stamens  and  two  fertile  stamens.  The  connectives  in  the 
latter  are  long  and  filamentous  and  each  bears  at  the  upper  part  a  normal  pollen  sac  and 
at  the  lower  end  a  non-fertile  enlarged  portion  which  the  insect  pushes  against  in  entering 
the  flower  and  thus  causes  the  pollen  to  be  deposited  on  its  back. — A-C,  aftei  Gray;  D-F, 
after  Wanning. 

When  the  divisions  of  the  calyx  and  corolla  remain  separate 
and  distinct  the  latter  are  spoken  of  as  CHORISEPALOUS  and  CHORI- 
PETALOUS,  respectively;  but  when  the  divisions  are  united  or 


384 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  224.  Lobelia  inflata:  A,  upper  portion  of  shoot  showing  the  dentate-denticulate 
leaves,  the  bracted  racemes  with  flowers  and  inflated  capsules,  the  latter  developing  soon 
after  fertilization;  B,  flower  showing  linear  calyx  teeth  and  2-lipped  corolla,  the  upper 
lip  with  2  rather  erect  lobes  and  the  lower  lip  spreading  and  3-cleft;  C,  longitudinal  section 
of  flower  showing  the  ovary  with  ovules  (o),  style  (s),  hairy  bifid  stigma  (t) ,  united  stamens 
(a),  corolla  (p)  and  calyx  (c) ;  D,  longitudinal  section  of  stamen  showing  the  hairy  summit. 

Scutellaria  pilosa:  R,  branch  showing  crenate  leaves  and  helmet-shaped  capsular 
fruits;  F,  capsule  after  dehiscence  showing  nutlets  (n).  G,  section  of  flower  of  Scutellaria 
lateriflora  showing  calyx  (c)  with  crest  on  one  side,  2-lipped  corolla  (p),  the  didynamous 
stamens  (s),  and  4-locular  ovary  (n). 

Spearmint  (Mentha  spicata}:  H,  showing  flowers  in  slender  interrupted  spikes;  J, 
flower  with  bell-shaped  calyx,  tubular  corolla  and  2-lobed  stigma;  K,  ellipsoidal  pollen 
grains. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


385 


coalesced  the  calyx  and  corolla  are  called  GAMOSEPALOUS   (syn- 
sepalous)   and  GAMOPETALOUS   (sympetalous),  respectively. 

When  the  divisions  of  the  calyx  or  corolla  are  entirely  united 
these  elements  are  said  to  be  ENTIRE,  and  when  the  divisions  are 


FIG.  225.  Flowers  of  Solanaceae.  Solatium  carolinense:  A,  portion  of  shoot  showing 
a  short  raceme  of  flowers  and  the  spinose  leaves  and  stems;  B,  diagram  of  cross  section 
of  flower  showing  sepals  (s),  petals  (p),  stamens  (a)  and  ovary  (c);  C,  longitudinal  section 
of  flower,  the  letters  the  same  as  in  B;  D,  stamen  showing  terminal  pores;  E,  two  spheroidal 
pollen  grains;  F,  cross  section  of  2-locular  berry. 

Hyoscyamus  mulicus:  G,  section  of  flower  showing  calyx  (c),  lobed  corolla  (p),  stamens 
inserted  on  corolla  tube  (s)  and  ovary  (o)  bearing  at  the  summit  a  long  style;  H,  pollen 
grains  in  different  views;  J,  portion  of  stalk  with  fruits  showing  cylindrical  calyx,  the 
fruit  really  being  enclosed  within  the  calyx  and  in  the  nature  of  a  pyxis. 

partly   united   they   are   spoken   of   as    "  toothed/'   "  lobed,"   or 
"  parted,"  according  to  the  degree  of  union. 

In  the  flowers  of  the  Cruciferae  and  Caryophyllaceae  there  is  a 

conspicuous  stalk  to  each  of  the  separate  petals,  which  is  known 

as  the  UNGUIS  or  CLAW;  while  the  upper  outspreading  portion  is 

known  as  the  LAMINA  or  blade.     In  the  gamosepalous  calyx  and 

25 


386 


A  TEXT-BOOK  OF  BOTANY. 


the  gamopetalous  corolla  the  lower  united  portion  is  known  as  the 
TUBE,  and  the  upper  outspreading  portion  as  the  LIMB  or  "  border." 
The  form  of  the  calyx  and  corolla  is  quite  characteristic  for  a 
number  of  important  families.  In  the  Compositae  there  are  two 
characteristic  forms  of  corolla,  namely,  the  tubular  in  the  disk 


FIG.  226.  Apocynum  androsami folium:  A,  portion  of  a  flowering  branch;  B,  a  flower 
showing  the  short  calyx  tube  and  the  corolla  with  more  or  less  spreading  lobes;  C,' longi- 
tudinal section  of  flower:  c,  calyx  teeth;  p,  corolla  lobes;  a,  anthers;  and  p,  ovary;  D, 
single  stamen  with  long  spurs  (s).  E,  a  flower  of  A.  cannabinum  showing  the  corolla  with 
ascending  lobes. 

flowers  and  the  ligulate  in  the  ray  flowers;  in  the  Papilionatae 
the  corolla,  from  its  fancied  resemblance  to  a  butterfly,  is  de- 
scribed as  PAPILIONACEOUS  (Fig.  221,  B)  ;  in  the  Labiatae  the 
petals  are  united  into  two  lip-like  divisions,  and  the  corolla  is  said 
to  be  BILABIATE  (Fig.  223,  F).  There  are  two  kinds  of  bilabiate 


MORPHOLOGY  OF  HIGHER  PLANTS. 

•t 


387 


K 


FIG.  227.  Flowers  of  the  Composites.  Inula  Helenium:  A,  ligulate  floret;  B,  tubular 
floret;  C,  achene  with  pappus;  D,  pollen  grains;  E,  united  anthers  showing  hooked  hairs 
(h)  at  the  base. 

F,  tubular  floret  of  Safflower  (Carthamus  tinctorius). 

Dandelion  (Taraxacum  officinale):  G,  ligulate  floret;  H,  one  of  the  achenes  showing 
spreading  pappus  on  a  long  stalk  which  develops  after  fertilization. 

J,  ligulate  floret  of  Coltsfoot  (Tussilago  Far  far  a). 

Marigold  (Calendula  officinalis):  K,  ligulate  floret;  L,  one  of  the  double  hairs  from 
corolla,  c,  corolla;  s,  stamens;  t,  stigmas;  p,  pappus;  h,  hairs. 


388  A  TEXT-BOOK  OF  BOTANY. 

corollas — one,  as  in  lavender,  where  the  mouth  of  the  tube  is  open, 
known  as  RINGENT  ;  and  another,  where  the  mouth  is  closed,  as  in 
Linaria,  called  PERSONATE. 

There  are  a  number  of  other  special  forms  of  calyx  and  corolla, 
particularly  the  latter,  and  of  these  may  be  mentioned  the  follow- 
ing :  A  corolla,  like  that  of  the  harebell,  which  is  more  or  less  bell- 
shaped,  is  termed  CAMPANULATE;  a  more  or  less  campanulate 
corolla  contracted  near  the  opening,  as  in  Gaultheria,  is  spoken 
of  as  URCEOLATE  or  urn-shaped ;  in  the  morning  glory  and  other 
Convolvulacese  the  corolla  is  said  to  be  INFUNDIBULIFORM  or 
funnel-shaped;  a  corolla  in  which  the  limb  spreads  abruptly  from 
the  tube,  as  in  Phlox  and  coffee,  is  termed  HYPOCRATERIFORM 
or  salver-shaped ;  a  corolla  with  a  short  tube  and  outspreading 
limb,  as  in  potato,  is  said  to  be  ROTATE  or  wheel-shaped ;  a  rotate 
corolla  with  the  margin  more  or  less  upturned  is  called  CRATERI- 
FORM  or  saucer-shaped ;  in  aconite  the  upper  petal  is  hood-  or  hel- 
met-shaped, and  the  corolla  is  spoken  of  as  GALEATE  ;  in  the  violets 
one  of  the  petals  has  a  spurred  appendage  and  the  corolla  is  de- 
scribed as  SACCATE  or  calcarate,  while  the  modified  petal  in  the 
orchids  is  known  as  the  LABELLUM. 

DURATION  OF  CALYX  AND  COROLLA. — There  is  considerable 
difference  in  the  length  of  time  that  the  calyx  and  corolla  persist, 
not  only  with  reference  to  each  other  but  in  different  plants.  The 
parts  are  said  to  be  CADUCOUS  when  they  drop  from  the  flower  as 
soon  as  it  opens,  as  the  calyx  of  the  poppy ;  when  they  remain  for 
a  day  or  so,  they  are  said  to  be  EPHEMERAL  or  fugacious,  as  in 
the  petals  of  the  poppy ;  in  the  rose  and  apple  the  petals  fall  away 
soon  after  the  pollen  reaches  the  stigma  and  they  are  said  to  be 
DECIDUOUS  ;  in  some  flowers  the  petals  wither  but  persist  until  the 
maturing  of  the  fruit,  as  in  the  Droseracese,  and  are  known  as 
MARCESCENT  ;  the  calyx  may  remain  unaffected  until  the  maturing 
of  the  fruit,  as  in  the  Labiatse,  when  it  is  said  to  be  PERSISTENT. 

Bracts. — In  addition  to  the  floral  envelopes,  other  more  or 
less  modified  leaves  are  borne  on  the  flower  branch  below  the 
flower,  frequently  at  the  base  of  the  flower  stalk,  and  these  have 
received  the  name  BRACTS.  The  bracts  closely  resemble  the  foli- 
age leaves,  but  usually  are  smaller  and  frequently  are  mere  scales, 
without  chlorophyll.  In  some  cases,  however.,  they  are  large  and 


MORPHOLOGY  OF  HIGHER  PLANTS.  389 

showy,  looking  like  petals  (petaloid),  as  in  the  water  arum  (Fig. 
263),  the  common  dogwood;  Bougainvillea  and  Poinsettia  seen 
in  greenhouses. 

The  Torus  constitutes  the  terminal  portion  of  the  flower 
axis  or  stalk,  and  is  usually  more  or  less  conical  and  somewhat 
enlarged.  When  the  torus  is  of  this  shape  the  parts  of  the  flower 
are  inserted  upon  it  in  serial  succession,  all  of  the  other  parts 
arising  below  the  pistil.  It  may,  however,  be  modified  into  a 
hollow  or  cup-like  structure  which  grows  up  around  the  ovary, 
carrying  the  other  parts  of  the  flower  (sepals,  petals,  and  stamens) 
with  it,  thus  changing  the  relative  position  of  the  parts,  although 
it  should  be  understood  that  the  ovary  occupies  practically  the 
same  position  in  the  two  cases. 

When  the  torus  is  of  the  first  type  and  the  other  parts  of  the 
flower  are  inserted  below  the  ovary,  the  flower  is  said  to  be  HYPO 
GYNOUS,  as  in  the  orange  flower  (Fig.  78,  A)  and  the  ovary 
superior;  but  when  the  torns  forms  a  cup-shaped  receptacle  and 
the  other  parts  of  the  flower  arise  on  its  margin  above  the  ovary, 
the  flower  is  called  EPIGYNOUS,  as  in  the  clove  (Fig.  78,  B ;  223  C) 
and  the  ovary  inferior.  In  other  cases  a  ring  of  leaf-like  tissue 
arises  from  the  torus,  forming  a  cup-like  receptacle  or  tube  which 
is  known  as  the  perianth  tube,  the  sepals,  petals,  and  stamens  being 
inserted  on  its  margin.  The  perianth  tube  may  be  free  from  the 
ovary,  when  the  flower  is  said  to  be  PERIGYNOUS  and  the  ovary  half 
inferior  or  half  superior,  as  in  cherry  (Fig.  223,  B)  ;  or  in  the 
case  of  an  epigynous  flower  it  may  form  a  prolongation  of  the 
cup-shaped  torus. 

Prefloration  or  estivation  is  the  arrangement  of  the  parts  of 
the  flower — more  especially  the  calyx  and  corolla — in  the  bud. 
Some  of  the  terms  used  in  this  connection  are  also  employed  in  the 
study  of  vernation.  The  following  are  some  of  the  terms  which 
are  employed:  VALVATE,  when  the  sepals  or  petals  meet  each 
other  at  the  edges,  as  in  Malvaceae ;  IMBRICATED,  when  the  sepals 
or  petals  overlap  each  other,  as  in  the  Magnoliacese ;  PLICATE  or 
PLAITED,  when  the  divisions  are  united  and  folded  together,  as  in 
the  petals  of  Convolvulus  and  Datura. 

The  sepals  and  petals  do  not  necessarily  possess  the  same 
arrangement,  as  in  the  Onagraceae,  where  the  sepals  are  valvate 


390  A  TEXT-BOOK  OF  BOTANY. 

and  the  petals  are  convolute.  Furthermore,  in  addition  to  the 
principal  types  of  estivation  and  vernation  already  given,  there 
are  a  number  of  special  modifications  of  these,  depending  upon 
the  number  and  arrangement  as  well  as  direction  of  the  over- 
lapping parts  of  the  flower-  or  leaf-bud. 

Coalescence  and  Adhesion. — Not  only  may  the  divisions  of 
the  same  circle  or  whorl  of  the  flower  be  united,  but  even  those 
of  different  circles,  and  a  number  of  terms  are  used  to  describe 
these  modifications. 

When  the  divisions  of  the  same  circle  are  united  there  is  said 
to  be  a  COHESION  or  COALESCENCE  of  the  parts.  When  the  divi- 
sions of  different  circles  are  united,  as  of  stamens  with  corolla, 
the  union  is  spoken  of  as  ADHESION  or  adnation,  as  in  Convolvulus. 

Chorisis  and  Multiplication  of  Parts. — In  contrast  with  the 
reduction  in  number  of  parts  of  the  flower  due  to  union,  there  may 
be  an  increase  in  the  number  of  parts  due  to  simple  division  or 
splitting  of  the  parts,  and  this  is  known  as  chorisis  or  deduplica- 
tion.  An  illustration  of  this  is  furnished  by  the  stamens  of  the 
orange  flower,  where  from  a  single  initial  stamen  or  primordium 
a  group  of  from  3  to  n  stamens  may  be  produced.  In  other  cases 
there  may  be  a  multiplication  in  the  number  of  parts  from  the 
beginning,  each  part  arising  independently  on  the  torus,  as  in  the 
stamens  of  rose.  This,  of  course,  would  not  be  termed  chorisis,  as 
no  splitting  or  branching  takes  place. 

Double  Flowers. — In  double  flowers  there  is  an  increase 
in  the  number  of  petals,  which  is  considered  to  be  due  to  the 
methods  of  cultivation  and  the  stimulus  of  an  increased  food- 
supply.  This  results  in  several  ways :  ( i )  By  transformation  of 
the  sporophylls,  more  particularly  the  stamens,  into  petals;  (2) 
by  division  or  chorisis  of  the  stamens  or  carpels  with  subsequent 
transformation  into  petals;  (3)  by  division  or  branching  of  the 
petals;  and  (4)  by  the  production  of  new  series  of  petals.  The 
extra  petals  in  double  carnations  and  double  roses  trace  their 
origin  to  the  stamens,  while  in  Fuchsia  they  are  the  result  of 
chorisis  of  the  petals. 

In  the  snow-ball  (Viburnum  Opulus)  and  hydrangea  the  essen- 
tial elements  have  undergone  a  complete  transformation,  and  the 
flowers,  while  large  and  showy,  are  sterile.  In  the  white  water  lily 


MORPHOLOGY  OF  HIGHER  PLANTS.     395 

(Nyniphaa)  there  is  a  series  of  parts  ranging  from  stamens  with 
narrow  filaments  and  stamens  with  broad  petaloid  filaments  to 
petals  tipped  with  a  small  anther  and  regular  petals  (Fig.  221,  A). 
In  this  case  the  stamens  are  considered  to  result  from  the  trans- 
formation of  the  petals.  In  the  case  of  green  roses  and  green 
strawberry  flowers  the  petals  become  green  and  leaf-like,  and  the 
change  is  spoken  of  as  CHLOROSIS  or  CHLORANTHY.  In  some 
flowers  even  the  ovules  are  replaced  by  leaf-like  processes  or 
appendages,  as  in  Drosera  and  clover. 

Arrested  Development. — The  arrest  or  suppression  of  parts 
of  the  plant,  particularly  of  the  flower,  is  of  very  common  occur- 
rence. Just  as  there  are  millions  of  seeds  that  never  find  suitable 
conditions  for  germination,  so  in  the  flowers  of  a  large  number 
of  plants  a  very  large  proportion  of  the  ovules  never  develop 
into  seeds,  the  plants  in  many  instances  not  furnishing  sufficient 
nutriment  for  all  of  the  ovules  to  mature.  Under  Leaves  it 
was  stated  that  in  the  axil  of  each  leaf  there  is  a  bud.  This  is 
not  always  apparent,  but  if  the  plant  be  subjected  to  some  special 
stimulus,  some  of  the  latent  buds  will  become  evident.  For 
example,  the  rubber  plant  (Ficus),  so  commonly  cultivated  as  an 
ornamental  plant,  shows  a  tendency  to  develop  a  straight,  un- 
branched  shoot,  but  if  the  tip  of  the  shoot  be  cut  off,  the  buds  in 
the  axils  of  the  upper  leaves  will  develop  into  branches,  while 
some  of  those  lower  down  will  form  small  protuberances,  but 
develop  no  further.  In  other  cases  there  is  a  loss  of  parts  which 
seems  to  be  due  to  loss  of  function.  When  there  is  a  partial  loss 
of  the  element,  as  of  the  anthers  in  the  flower  of  catalpa,  it  is 
said  to  be  imperfectly  developed  or  ABORTIVE.  When  the  entire  ele- 
ment remains  undeveloped,  as  in  some  of  the  stamens  of  the  Labi- 
atae,  it  is  said  to  be  SUPPRESSED  (Fig.  223,  F) .  In  flax  the  stamens 
of  the  outer  whorl  are  reduced  to  thread-like  processes.  Such 
sterile  or  aborted  stamens  are  called  STAMINODES  (staminodia). 
In  other  plants  the  parts  are  not  apparently  arrested,  but  have  not 
yet  been  differentiated,  as  is  the  case  in  the  Lily  family,  where  the 
perianth  is  composed  of  segments  which  are  more  or  less  alike 
(Fig.  269).  In  other  cases,  however,  there  seems  to  be  a  suppres- 
sion or  arrest  of  the  floral  envelopes. 

Cleistogamous  Flowers. — In  addition  to  the  regular  flowers 


392  A  TEXT-BOOK  OF  BOTANY. 

some  plants  produce  cleistogamous  or  closed  flowers.  In  these 
flowers  the  corolla  is  usually  suppressed.  The  flowers  develop 
stamens  and  pistils  but  remain  closed,  and  thus  there  is  no  chance 
for  cross-pollination.  The  cleistogamous  flowers  appear  later 
than  the  regular  flowers  and  are  more  or  less  inconspicuous, 
developing  under  the  leaves  and  sometimes  underground.  Of  the 
plants  producing  cleistogamous  flowers,  the  following  may  be 
mentioned :  various  species  of  Viola,  Polygala,  etc. 

Classes  of  Flowers. — As  we  have  seen,  the  megasporophylls 
and  microsporophylls  in  the  Gymnosperms  are  borne  on  separate 
branches,  thus  giving  rise  to  two  kinds  of  flowers  or  cones.  While 
the  separation  of  the  stamens  and  pistils  is  exemplified  in  a 
number  of  plants  in  the  Angiosperms,  still  it  is  not  the  rule, 
and  these  two  elements  are  usually  borne  close  together  on  the 
same  axis, — i.e.,  they  both  enter  into  a  single  flower  structure. 
Such  a  flower  is  said  to  be  HERMAPHRODITE  or  bisexual,  and  most 
of  the  conspicuous  flowers  are  of  this  kind,  as  roses,  buttercups, 
lilies,  etc.  Inasmuch  as  the  stamens  and  pistils  constitute  the  essen- 
tial elements  of  the  flower,  hermaphrodite  flowers  are  also  spoken 
of  as  PERFECT,  providing  the  stamens  and  pistils  are  capable  of 
exercising  their  generative  functions.  When  the  stamens  and 
pistils  occur  in  separate  flowers  the  flowers  are  said  to  be  UNI- 
SEXUAL or  IMPERFECT,  as  in  willow,  oak,  hickory,  etc.  A  flower 
having  only  a  pistil  or  pistils  is  called  PISTILLATE  (Fig.  219, 
A),  while  one  having  only  a  stamen  or  stamens  is  STAMINATE,  as  in 
oaks.  The  staminate  and  pistillate  flowers  may  be  borne  on  the 
same  plant,  when  it  is  said  to  be  MONOECIOUS,  as  in  castor  bean, 
chestnut,  -hickory,  alder ;  or  they  may  be  borne  on  separate  plants, 
when  the  plant  is  called  DICECIOUS,  as  in  willows  and  poplars. 
Plants  bearing  hermaphrodite  and  unisexual  flowers  on  the  same 
individual  plant  or  on  different  individuals  are  called  POLYGAMOUS, 
as  in  Ailanthus. 

A  COMPLETE  flower  is  one  which  possesses  both  kinds  of  essen- 
tial elements  and  both  kinds  of  floral  envelopes,  and  is  SYMMET- 
RICAL when  a  plane  can  be  laid  in  all  directions,  the  parts  being 
alike,  and  when  the  number  of  parts  in  each  circle  is  the  same  or 
when  the  number  in  one  circle  is  a  multiple  of  that  in  the  others ; 
as  a  rule,  the  number  of  stamens  is  some  multiple  of  one  of  the 


MORPHOLOGY  OF  HIGHER  PLANTS.  393 

other  parts,  as  in  geranium  (Fig.  223),  where  we  find  five  sepals, 
five  petals,  ten  stamens,  and  five  pistils. 

Flowers  are  also  spoken  of  as  REGULAR  or  IRREGULAR,  accord- 
ing to  whether  all  the  parts  of  a  circle  are  uniform  in  shape  or 
not;  the  flowers  of  geranium  are  regular,  while  those  of  violets 
are  irregular.  Regular  flowers  are  also  spoken  of  as  ACTINO- 
MORPHIC  or  RADIAL,  and  irregular  flowers  as  ZYGOMORPHIC.  The 
latter  are  also  spoken  of  as  DORSIVENTRAL.  Dorsiventral  flowers 
either  arise  as  such,  as  in  some  of  the  Leguminosae  (Fig.  231), 
or  they  may  arise  as  radial  flowers  and  become  dorsiventral  dur- 
ing the  course  of  development,  as  in  willow  herb  (Fig.  224). 

In  some  flowers  the  floral  envelopes  are  wanting,  and  the 
flowers  are  said  to  be  NAKED,  as  in  the  willows  and  grasses. 

ANTHOTAXY. — The  study  of  the  arrangement  of  flowers  on 
the  stem  is  known  as  anthotaxy.  The  flowering  axis  may  bear 
only  a  single  terminal  flower,  as  in  Tulipa;  or  the  flowers  may 
occur  singly  in  the  axils  of  the  leaves,  as  in  Viola  canadensis. 
When,  on  the  other  hand,  the  flowers  are  borne  upon  a  branch 
shoot,  the  internodes  of  which  are  more  or  less  condensed,  and 
the  leaves  smaller  and  of  a  more  simple  structure  than  the 
foliaceous  leaves,  the  whole  shoot  is  known  as  an  INFLORESCENCE, 
and  the  leaves  are  called  BRACTS.  The  flower  thus  represents  a 
single  unbranched  shoot,  while  the  inflorescence  represents  a 
branched  or  ramified  shoot. 

The  so-called  bracts,  besides  being  generally  smaller  than  the 
leaves  proper,  are  mostly  sessile ;  they  may,  however,  be  green,  or 
membranaceous,  or  they  may  exhibit  a  bright  coloration,  as  in 
Monarda. 

The  stalk  of  the  individual  flower  is  called  a  PEDICEL,  and 
may  be  naked,  or  bear  one  or  two  small  bracts,  which  are  called 
FORE-LEAVES  or  PROPHYLLA.  In  the  monocotyledons  there  is 
usually  only  one  fore-leaf,  which  turns  its  back  to  the  mother-axis 
and  is  frequently  two-nerved  and  two-keeled.  In  the  dicotyledons 
there  are  generally  two  fore-leaves,  which  are  placed  to  the  right 
and  left  of  the  flower,  as  in  the  violets. 

The  position  of  the  floral  leaves  (the  sepals,  the  petals  and 
those  of  the  perianth)  depends  upon  the  arrangement  of  the 
fore-leaves,  so  that  in  most  of  the  monocotyledons,  where  there 


394  A  TEXT-BOOK  OF  BOTANY. 

is  one  mediane  prophyllon,  the  first  leaf  of  the  perianth  is  placed 
on  the  front,  while  the  two  succeeding  leaves  of  the  perianth 
occupy  a  position  of  120°  from  this  (Fig.  254).  When,  on  the 
other  hand,  as  in  the  dicotyledons  with  pentamerous  flowers, 
two  fore-leaves  are  developed,  the  first  floral  leaf  (sepal)  is 
situated  obliquely  above  the  last  fore-leaf,  usually  on  the  frontal 
part  of  the  flower;  the  second  sepal  is  directly  behind  the  first 
or  diagonally  opposite  to  it,  the  remaining  three  leaves  (sepals) 
occurring  in  a  spiral  of  two-fifths  (Fig.  280).  Several  deviations 
from  this  type  occur,  as  in  Lobelia  (Fig.  224),  Polygala,  etc. 

Two  types  of  inflorescence  are  distinguished:  (i)  The  IN- 
DEFINITE, in  which  the  flowers  open  or  develop  in  acropetalous 
or  centripetal  succession,  and  (2)  the  DEFINITE,  in  which  the 
flowers  open  in  basipetalous  or  centrifugal  succession.  The  in- 
definite type  of  inflorescence  is  seldom  terminated  by  an  ex- 
panded flower,  and  two  classes  of  this  type  are  distinguished : 
(a)  Those  in  which  the  flowers  are  pedicelled,  as  in  the  raceme 
(Fig.  267)  and  umbel  (Fig.  344),  and  (b)  in  which  the  flowers 
are  sessile,  as  in  the  spike  (Fig.  230)  and  head  (Fig.  228). 

The  RACEME  is  a  long  inflorescence  with  pedicelled  flowers, 
which  are  frequently  subtended  by  bracts  (Figs.  224,  225,  and 
293)-  The  CORYMB  is  a  modified  raceme  in  which  the  pedicels 
of  the  basal  flowers  are  much  longer  than  those  of  the  apical, 
and  thus  the  inflorescence  looks  like  an  umbel.  In  the  milkweed 
the  flowers  have  pedicels  of  the  same  length  which  arise  from  the 
apex  of  the  shoot  or  peduncle,  and  this  form  of  inflorescence  is 
known  as  an  UMBEL.  In  the  Umbelliferae  a  flower  cluster  or 
umbellet  takes  the  place  of  the  individual  flowers  of  the  umbel, 
and  is  known  as  a  COMPOUND  UMBEL  (Figs.  346-348). 

The  SPIKE  is  also  generally  a  long  inflorescence,  the  flowers 
being  sessile  (Fig.  230,  illus.  3),  the  secondary  spikes  in  grasses 
being  known  as  SPIKELETS.  The  SPADIX  is  a  form  of  spike, 
which  is  readily  distinguished  by  the  fleshy  stem,  in  which  the 
flowers  are  frequently  deeply  imbedded,  and  which  is  frequently 
surrounded  by  a  large  bract,  the  so-called  SPATHE,  as  in  Arissema. 
The  CATKIN  is  a  kind  of  spike  with  small,  often  imperfect  flowers, 
which  falls  off  as  a  whole,  as  in  the  staminate  catkins  of  the 
oak.  The  catkins  are  mostly  decompound,  and  in  some  species 


MORPHOLOGY  OF  HIGHER  PLANTS.     395 

of  Populus  the  single  flowers  are  pedicelled,  and  hence  are  actually 
racemose  rather  than  spicate  inflorescences. 

In  the  head  and  the  umbel  the  main  inflorescential  axis  is 
exceedingly  short  and  the  innermost  flowers  are  often  destitute 
of  bracts,  in  contrast  with  the  external,  which  are  frequently 
provided  with  bracts  that  are  of  quite  considerable  size.  Sterile 
bracts  also  occur  in  these  two  types,  and  are  called  involucral 
leaves,  as  in  Cornus  florida,  where  they  are  white  or  pink.  There 
is  also  a  difference  in  sex  of  the  outer  and  inner  flowers.  While 
the  head  occurs  as  typical  inflorescence  in  the  Compositse,  it  also 
exists  in  some  of  the  L^mbelli ferae. 

The  flowers  of  the  Composite?  are  borne  on  a  common  torus, 
known  as  the  disk,  which  is  subtended  by  one  or  more  circles  of 
bracts,  these  constituting  an  INVOLUCRE.  The  flowers  are  of  two, 
kinds,  and  they  receive  different  names  because  of  their  form  and, 
position.  Those  situated  near  the  margin  of  the  disk  are  known 
as  RAY-FLOWERS,  and  because  they  possess  more  or  less  strap- 
shaped  corollas  are  also  known  as  LIGULATE  FLOWERS.  Those 
occupying  the  central  portion  of  the  disk  are  known  as  DISK- 
FLOWERS,  or  as  TUBULAR  FLOWERS  because  of  the  tubular  shape  of 
the  corolla.  Most  of  the  Composite  possess  both  ligulate  and 
tubular  flowers,  as  Arnica,  Matricaria  (Fig.  228),  the  common 
daisy,  etc.  But  some  of  the  members  of  the  family  have  only 
ligulate  flowers,  as  chicory  and  dandelion,  and  a  relatively  few 
have  only  tubular  flowers. 

Two  types  of  definite  inflorescence  are  distinguished :  ( I ) 
the  DIBRACHIOUS  (bifurcate)  CYME  in  which  the  inflorescence 
represents  a  series  of  very  regularly  arranged  lateral  axes,  one 
on  each  side  of  the  terminal  or  median  flower,  as  in  the  Caryo- 
phyllaceae;  and  (2)  the  MONOBRACHIOUS  (simple)  CYME,  of  which 
there  are  several  modifications,  but  common  to  all  of  them  is  the 
development  of  only  one  lateral  branch  to  each  terminal  flower. 
In  the  SCORPIOID  cyme  the  lateral  axes  are  arranged  alternately 
to  the  right  and  left,  while  in  the  HELICOID  cyme  the  lateral  axes 
are  all  on  the  same  side  of  the  main  axis,  as  in  Hypericum.  The 
so-called  flower  cluster  is  a  cymose  inflorescence  of  either  the 
definite  or  indefinite  type  in  which  the  flowers  are  almost  sessile 
or  very  short  pedicelled,  as  in  Chenopodium,  Juncus,  etc.  Some- 


396 


A  TEXT-BOOK  OF  BOTANY. 


times  the  inflorescence  may  be  decompound  or  complex,  as  in 
several  Composite,  where  the  heads  may  be  arranged  in  cymes 
or  racemes;  or,  as  in  the  Graminese,  where  the  spikelets,  which 


FIG.  228.  Matricaria:  A,  longitudinal  section  of  head  showing  torus  (a),  involucre 
(b),  ray  florets  (c)  and  disk  florets  (d).  B,  head  with  the  florets  removed,  showing  the  long 
conical  torus  and  the  involucre  (H).  C,  tubular  floret  showing  the  ovary  (f)  with  glandular 
hairs  (D1)  and  the  embryo  (S),  which  develops  after  fertilization;  style  (g)  and  bifid  stigma 
(N),  the  surface  of  which  is  covered  with  hairs;  n,  nectaries;  b,  corolla  tube  with  narrow 
lobes  (a);  stamens  showing  filaments  (st),  united  anthers  (A)  and  apex  of  connective  (sp). 
D,  ligulate  floret  showing  ovary  (F),  and  bifid  stigma  (N);  tube  of  corolla  (R)  and  the 
upper  ligulate  portion  (Z). — After  Meyer. 

are  spikes,  may  be  arranged  in  panicles,  i.e.,  branched  racemes; 
or  finally,  as  in  Cryptotaenia  (Umbelli ferae),  where  the  umbels 
are  arranged  in  cymes. 


MORPHOLOGY  OF  HIGHER  PLANTS.     397 

Pollination  and  Fertilization. — Fertilization  represents  the 
final  stage  in  the  work  of  the  flower  as  a  whole,  and  has  already 
been  defined  as  the  union  of  the  egg-cell  and  a  male  nucleus. 
Pollination  may  be  considered  to  include  the  transferral  of  the 
pollen  grains  from  the  anther  to  stigma  and  their  subsequent 
germination  thereon,  this  latter  process  resulting  in  the  produc- 
tion of  the  male  nuclei.  Pollination  thus  represents  but  one  series 
of  changes  or  processes  which  precede  fertilization,  for,  while  the 
pollen  grain  is  going  through  the  various  stages  in  development 
which  lead  to  the  formation  of  the  male  nuclei,  a  series  of  com- 
plex changes  are  going  on  in  the  embryo-sac  leading  to  the  develop- 
ment of  the  egg-cell. 

Our  special  interest  in  pollination  arises  from  the  fact  that  the 
pollen  grains  are  not  retained  in  the  pollen  sacs  and  are  dependent 
upon  various  agencies  for  transferral  to  the  stigma.  This  is  a 
matter  of  great  biological  significance,  for  it  is  claimed  that  many 
of  the  special  characters  of  flowers  have  a  direct  relation  to 
pollination. 

The  various  ways  in  which  the  anthers  open  for  the  discharge 
of  the  pollen  when  it  is  ripe  have  already  been  considered  (Fig. 
221),  but  it  may  be  added  that  the  manner  in  which  this  is  done 
usually  appears  to  have  a  relation  to  the  manner  in  which  the 
pollen  is  to  be  carried  to  the  stigma.  In  order  that  pollination 
may  be  effected,  the  stigma  must  be  ripe  or  mature,  when  it  is 
said  to  be  receptive.  It  then  usually  secretes  a  sticky,  sugary 
liquid  which  causes  the  pollen  grains  to  adhere  to  the  stigmatic 
surface  (Fig.  83),  and  which  at  the  same  time  serves  as  a  nutrient 
to  them.  Usually  the  pollen  grains  begin  to  germinate  in  a  short 
time  after  reaching  the  stigma,  which  is  made  evident  by  the  pro- 
trusion of  the  pollen  tubes.  The  stigma  seems  also  to  have  the 
power  of  selection,  for  in  many  cases  the  pollen  does  not  germi- 
nate as  readily  on  the  stigma  of  the  same  flower  as  on  that  of 
another  flower,  provided  it  be  of  the  same  or  a  nearly  related 
species. 

When  a  flower  possesses  both  stamens  and  pistils, — that  is,  is 
bisexual  or  hermaphrodite, — and  its  pollen  germinates  upon  its 
own  stigma,  the  process  is  known  as  close  or  SELF-POLLINATION, 
and  if  fertilization  follows,  this  is  known  as  SELF-FERTILIZATION. 


398  A  TEXT-BOOK  OF  BOTANY. 

While  most  hermaphrodite  flowers  are  self-pollinated,  there  are 
some  that  are  not,  and  this  is  brought  about  in  several  ways : 
(i)  As  already  pointed  out,  the  pollen  may  germinate  better  on 
the  stigma  of  another  flower  than  on  the  stigma  of  the  same 
flower.  (2)  The  anthers  and  pistils  of  the  same  flower  may  mature 
at  different  times,  and  this  is  one  of  the  commonest  ways  of 
preventing  self-pollination.  Usually  in  such  cases  the  stamens 
mature  first.  The  common  plantain  (Plantago)  furnishes  an 
example  of  the  maturing  of  the  stigma  before  the  anther.  The 
flowers  of  this  plant  are  arranged  in  spikes  (Fig.  230,  illus.  3 
and  4)  which  belong  to  the  indefinite  class,  and  hence  the  lower 
flowers  on  the  spike  expand  first.  As  stated,  the  pistil  of  each, 
flower  matures  first,  and  after  it  withers  the  stamens  protrude  an 
discharge  their  pollen.  It  is  evident  that  the  flowers  can  not  b 
self-pollinated,  nor  is  it  likely  that  one  flower  will  be  pollinated 
|by  another  of  the  same  spike.  (3)  The  stamens  and  pistils  of  the 
same  flower  may  vary  in  length,  as  in  Polygonum  (Fig.  230,  illus. 
i  and  2)  and  Lythrum  (Fig.  230,  illus.  5),  or  stand  in  such  other 
relation  to  each  other  that  self-pollination  will  not  be  effected, 
as  in  some  of  the  irregular  or  zygomorphic  flowers,  like  those  of 
Orchids.  In  these  several  cases  the  pollen  grains  either  fall  upon 
or  are  carried  by  various  agents  to  the  stigmas  of  other  flowers, 
and  this  is  known  as  CROSS-POLLINATION,  and  the  fertilization 
which  follows  as  CROSS-FERTILIZATION. 

Cross-fertilization  is  an  advantage  to  the  species,  for  usually 
the  seeds  which  result  from  this  process  give  rise  to  plants  which 
are  more  vigorous  and  otherwise  superior  to  those  which  result 
from  self-fertilization.  In  some  cases,  in  order  to  insure  the  pro- 
duction of  fruit,  hand-pollination  is  practised,  as  by  the  growers 
of  vanilla  and  some  other  tropical  plants  of  economic  importance. 

In  the  case  of  unisexual  flowers,  or  those  in  which  the  stamens 
and  pistils  are  in  separate  flowers,  there  is,  of  course,  no  chance 
for  self-pollination.  Here,  as  in  the  case  of  cross-pollinated  her- 
maphrodite flowers,,  pollination  may  be  more  or  less  close  or  it 
may  be  remote,  as  between  flowers  of  the  same  cluster  or  inflores- 
cence, between  flowers  of  different  clusters  or  inflorescences  on 
the  same  plant,  or  between  flowers  on  different  plants. 

In  buckwheat  (Fig.  230,  illus.  i  and  2)  and  partridge  berry 


MORPHOLOGY  OF  HIGHER  PLANTS. 


399 


(Mitchella  repens)  two  kinds  of  flowers  are  produced,  viz.:  (a) 
one  with  short  styles  and  long  filaments,  and  another  (b)  with 
long  styles  and  short  filaments,  and  thus  the  flowers  appear  to  be 
especially  adapted  for  insect  cross-pollination  and  are  called 
DIMORPHIC.  In  still  other  cases  one  species  gives  rise  to  three 
kinds  of  flowers,  depending  upon  the  difference  in  the  relative 
lengths  of  the  styles  and  filaments,  as  in  the  purple  loosestrife 
(Lythrum  calcaratum),  and  such  flowers  are  called  TRIMORPHIC. 
The  external  agents  which  are  instrumental  in  carrying  pollen 
from  one  flower  to  another  and  thereby  promoting  cross-pollina- 


FIG.  229.  Visitation  of  flowers  by  insects  showing  how  they  gather  the  pollen  and 
assist  in  cross-pollination,  the  one  on  the  left  being  Lilium  Martagon  visited  by  a  hawk 
moth,  showing  that  while  the  proboscis  is  removing  honey  from  the  nectary  the  under 
side  of  the  body  is  becoming  covered  with  pollen;  at  the  right  Cydonia  vulgaris,  the  common 
quince,  visited  by  a  bee,  whose  legs  are  becoming  covered  with  pollen. — After  Dodel-Port. 

tion  are  the  wind,  water  currents,  insects,  small  animals  and  birds, 
such  as  humming-birds,  which  are,  even  in  temperate  regions, 
to  be  observed  visiting  the  garden  nasturtium. 

In  many  of  the  early-flowering  trees,  as  well  as  pines,  Indian 
corn,  etc.,  the  flowers  are  devoid  of  showy,  attractive  features, 
but  produce  large  quantities  of  pollen  which  is  more  or  less  dry 
and  powdery  and  carried  by  the  wind  to  other  flowers.  Flowers 
which  are  wind-pollinated  are  classed  as  ANEMOPHILOUS,  and  it  is 
estimated  that  about  one-tenth  of  all  the  flower-producing  plants 
belong  to  this  class. 

Plants  which  are  pollinated  by  the  aid  of  water  currents  are 


400 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  230.  Manner  of  cross-pollination  in  some  hermaphrodite  flowers,  i,  2, 
Flowers  of  buckwheat,  showing  long  style  and  short  filaments  in  i ,  and  short  styles  and 
long  filaments  in  2:  a,  .anthers;  st,  stigmas;  n,  nectaries.  3,  Spike  of  plantain  showing 
maturing  of  stamens  below  and  pistils  above.  4,  Dissected  flower  of  plantain:  b,  bract; 
c,  calyx;  p,  corolla  tube;  s,  stamens;  t,  protruding  withered  style.  5,  Flowers  of  Purple 
willow-herb  (Lythrum  Salicaria) ,  one  side  of  the  perianth  removed  from  each.  A  is  long- 
styled,  B,  medium-styled,  and  C,  short-styled.  The  direction  of  the  arrows  and  dotted  lines 
indicates  the  best  methods  of  crossing. — i,  2,  5,  adapted  from  Warming. 


MORPHOLOGY  OF  HIGHER  PLANTS.     401 


FIG.  231.  A,  flowering  and  fruiting  plant  of  peanut  (Arachis  hypogcea).  After  fertiliza- 
tion the  carpophore  (or  stalk  between  calyx  and  ovary)  grows  in  length,  sometimes  4  to  8 
cm.,  and  curves  downward  penetrating  the  soil  (el),  after  which  the  fruit  develops.  B. 
longitudinal  section  through  the  papilionaceous  (bilateral)  flower;  C.  longitudinal  section 
through  the  pod  (peanut). — After  Taubert. 

known  as  HYDROPHILOUS,  and  under  this  head  are  included  those 
plants  which  live  under  the  water  and  those  that  produce  flowers 
at  or  near  the  surface  of  the  water. 

Those  plants  which  depend  upon  the  visitation  of  insects  for 
26 


402  A  TEXT-BOOK  OF  BOTANY. 

the  transferral  of  the  pollen  in  cross-pollination  are  called  ENTO- 
MOPHILOUS  (Fig.  229).  They  frequently  possess  bright,  highly 
colored  flowers,  and  it  is  considered  that  these  serve  as  an  attrac- 
tion to  the  insects  which  visit  them.  The  insects  are,  however, 
probably  more  attracted  by  the  odor  and  food  products  which 
they  obtain,  such  as  the  nectar.  The  nectar  is  secreted  by  glands 
known  as  nectaries,  which  are  variously  located ;  frequently 
they  are  on  the  torus,  either  between  the  ovary  and  stamens 
(Fig.  78)  or  between  the  stamens  and  petals.  Sometimes  the 
stamen  is  modified  to  a  nectar-secreting  spur,  as  in  the  violets. 
In  aconite  the  nectary  is  developed  from  one  of  the  posterior 
petals  (Fig.  223,  E).  In  seeking  the  nectar  the  pollen  of  the  ripe 
anther  may  fall  upon  or  adhere  to  the  insects  and  thus  be  carried 
from  one  flower  to  another  (Fig.  230). 

HONEY  is  a  product  formed  through  transformation  of  the 
plant  nectar  by  honey  bees.  The  nectar  is  supposed  to  be  acted 
upon  by  certain  salivary  secretions  of  the  bee  and  changed  into  a 
fruit-sugar,  the  so-called  honey,  consisting  of  a  mixture  of  dex- 
trose and  levulose.  The  nectar  of  buckwheat  and  clover  (partic- 
ularly white  clover)  is  the  principal  source  of  the  commercial 
article.  The  nectar  of  some  plants  is  poisonous  and  may  furnish  a 
poisonous  honey  (see  discussion  under  Ericaceae). 

THE  INNER  STRUCTURE  OF  THE  FLOWER. 

The  inner  structure  of  the  flower  bears  a  close  resemblance 
to  that  of  the  stem  and  leaf.  The  BRACTS  in  almost  all  particulars 
are  like  the  foliage  leaf  of  the  same  plant,  and  the  FLOWER  STALK 
closely  resembles  the  foliage  stem.  The  CALYX,  while  resembling 
the  foliage  leaf,  usually  contains  calcium  oxalate  in  greater  amount, 
and  the  chlorenchyma  consists  wholly  of  rather  loose  chlorophyll 
parenchyma ;  the  outer  or  under  epidermis  contains  the  stomata, 
and  if  hairs  are  present,  they  also  arise  from  this  surface;  the 
fibrovascular  bundles  are  generally  simple  in  structure,  although 
in  some  cases,  as  in  lavender,  sclerenchymatous  fibers  are  strongly 
developed. 

In  the  COROLLA  the  epidermal  cells  are  generally  more  or  less 
centrifugally  developed,  forming  prominent  papillae  (Fig.  232, 
A,  B),  which  give  the  petals  a  velvety  or  satiny  appearance,  as  in 


MORPHOLOGY  OF  HIGHER  PLANTS. 


403 


the  rose ;  glandular  and  non-glandular  hairs  are  also  developed 
which  are  peculiar  to  the  corollas  of  irregular  flowers,  as  in  La- 
vandula  vera  and  Viola  tricolor  (Figs.  124,  149-155,  232); 
stomata  are  comparatively  few  in  number.  The  epidermal  cells 


FIG.  232.  Inner  morphology  of  the  flower  as  illustrated  in  Viola  tricolor.  A,  epider- 
mal cells  from  the  outer  surface  of  the  spurred  petal  showing  papillae;  B,  epidermal  cells 
from  the  under  surface  of  the  petals,  some  of  the  cells  showing  centripetal  thickenings,  the 
two  without  thickenings  indicating  the  epidermal  mucilage-cells;  C,  epidermal  cells  from 
the  under  surface  of  the  petals  showing  a  zigzag  outline  and  short  centripetal  thickenings; 
D,  surface  view  of  the  mesophyll  of  the  petals;  E,  corkscrew-like  hair  from  the  innet  sur- 
face of  the  spurred  corolla  near  the  throat;  F,  a  hair  from  the  edge  of  an  anther;  G,  epider- 
mal cells  of  the  anthers;  H,  surface  view  of  the  mesophyll  cells  from  the  spurred  stamen 
showing  collenchymatous  thickening;  I,  surface  view  of  cells  of  endothecium;  K,  pollen 
grain  viewed  from  the  side;  L,  pollen  grain  examined  in  water;  M,  pollen  grain  observed 
in  chloral  solution. 

are  but  slightly  cutinized,  and  in  surface  view  are  strongly  undu- 
late and  appear  striate  owing  to  the  papillose  development  (Figs. 
232  and  235).  The  chlorenchyma  is  made  up  of  rather  loose, 
branching  parenchyma  cells  ( Fig.  232,  D ) ,  with  large,  intercellular 
spaces.  The  cells  are  free  from  chloroplastids,  may  contajn 


404  A  TEXT-BOOK  OF  BOTANY. 

chromoplastids,  or,  like  the  epidermal  cells,  a  colored  sap ;  in  some 
instances,  as  in  the  buttercups,  starch  grains  are  also  found  in 
the  mesophyll.  Calcium  oxalate  crystals  are  usually  present,  and 
milk  vessels  ate  sometimes  found,  as  in  the  Papaveraceae. 

The  FILAMENT  and  connective  possess  a  central  fibrovascular 
bundle,  around  which  are  arranged  comparatively  small  paren- 
chyma cells  and  among  which  secretion  cells  are  sometimes  scat- 
tered, as  in  Tilia.  The  pollen  sacs  consist  of  but  two  layers  of 
cells — an  outer  layer  called  the  "exothecium,"  which  resembles 
the  epidermis  of  the  corolla,  and  an  inner  layer  called  the  "  endo- 
thecium,"  the  cells  of  which  are  contractile  and  peculiarly  thick- 
ened, this  feature  being  rather  characteristic  for  certain  species 
(Fig.  232,  /).  Lining  the  pollen  sacs  during  their  development, 


FIG.  233.  Several  forms  ot  pollen  grains:  A,  crocus;  B,  arnica,  with  three  thin  places 
in  the  wall  through  one  of  which  the  pollen  tube  may  protrude;  C,  lavender  showing  six 
thin  places  in  the  wall. 

there  is  a  layer  of  cells,  called  the  "  tapetal  cells  " ;  but  these  are 
usually  sooner  or  later  absorbed. 

The  POLLEN  GRAINS  vary  greatly  in  number,  as  well  as  in 
size  and  shape.  They  are  usually  more  or  less  ellipsoidal,  but 
may  be  spherical,  as  in  Crocus  (Fig.  233,  A)  ;  more  or  less  three- 
sided,  as  in  the  Composite  and  in  cloves ;  four-  or  five-sided,  as  in 
Viola  tricolor  (Fig.  232,  K,  L,  M),  and  in  some  cases,  as  in  the 
Pinaceae,  they  may  be  winged.  In  addition  to  protoplasm  and 
one  or  more  nuclei,  pollen  grains  contain  considerable  oil  and 
starch.  The  outer  or  enclosing  membrane  (Fig.  233)  consists  of 
two  parts :  an  inner  one,  known  as  the  "  intine,"  and  consisting  of 
cellulose,  and  an  outer,  known  as  the  "  exine,"  apparently  con- 
sisting chiefly  of  cutin;  in  some  cases  the  exine  also  contains  an 
oil  which  is  colorless,  as  in  Salvia,  or  yellowish,  as  in  lavender, 
and  in  some  instances  it  may  contain  a  viscid  substance,  causing 


MORPHOLOGY  OF  HIGHER  PLANTS. 


405 


the  pollen  grains  to  adhere,  as  in  CEnothera.  The  grains  may  be 
smooth  or  variously  sculptured ;  in  most  instances  the  exine  is 
unevenly  developed,  leaving  thin  places  through  which  the  pollen 
tubes  protrude  in  germination;  these  give  the  appearance  of 


FIG.  234.  A,  Crocus  (Spanish  saffron)  showing  two  spherical  pollen  grains,  a  fragment 
of  stigma  with  papillae,  and  fragment  of  an  anther;  B,  Calendula  showing  3  spinose  pollen 
grains  and  fragment  of  corolla,  the  cells  of  which  contain  oil-like  globules;  C,  Carthamus 
(so-called  American  saffron)  showing  2  slightly  spinose  pollen  grains  and  a  fragment  of 
the  corolla  with  brown  laticif erous  vessels  and  numerous  unicellular  hairs. — After  Weakley. 

grooves  when  the  grains  are  dry,  and  the  number  of  grooves  is 
characteristic  for  different  species;  in  most  of  the  Composite 
they  are  three  in  number ;  in  the  Labiatae  there  are  six,  while  in 
Crocus  they  are  wanting  (Fig.  234). 

The  epidermal  cells  of  the  STIGMA  are  quite  characteristic. 


4o6  A  TEXT-BOOK  OF  BOTANY. 

The  cells  of  the  epidermis,  or  so-called  "  stigma-epithel,"  may  be 
palisade-like,  forming  a  more  or  less  wart-like  mass,  as  in  the 
viscous  stigmas  of  the  Umbelliferae,  or  the  outer  walls  may  be 
modified  to  rather  broad  papillae,  as  in  matricaria  and  arnica, 
or  they  may  be  developed  into  hair-like  processes,  as  in  crocus. 
The  pollen  tubes  either  enter,  the  style  through  an  open  canal, 
as  in  the  violets,  or  they  penetrate  into  the  conducting  tissues 
of  the  style,  either  through  the  papillae,  as  in  malva,  or  through 
the  middle  lamella  of  two  neighboring  papillae,  as  in  Atropa 
Belladonna. 

The  important  tissue  of  the  STYLE  is  the  conducting  tissue ;  in 
styles  which  are  hollow  it  forms  the  lining  of  the  canal,  the  cells 
resembling  those  of  the  stigma-epithel ;  in  styles  that  are  solid 
the  conducting  tissue  occupies  the  central  axis  and  consists  of 
somewhat  elongated  cells,  the  walls  of  which  are  generally  thick, 
frequently  strongly  refractive  and  possess  the  property  of  swell- 
ing, being  furthermore  separated  by  large  intercellular  spaces. 
Surrounding  the  conducting  tissue  are  thin-walled  parenchyma 
cells,  in  which  the  fibrovascular  bundles  are  distributed,  the  num- 
ber of  groups  of  the  latter  corresponding  to  the  number  of  carpels 
that  compose  the  gynaecium.  There  may  also  occur  secretion  cells, 
containing  mucilage,  as  in  malva,  or  oil  and  resin,  as  in  matri- 
caria. Occasionally,  the  parenchyma  is  replaced  either  in  part 
or  entirely  by  mechanical  cells,  and  the  epidermal  cells  may  be 
modified  to  hairs. 

The  tissues  of  the  OVARY  are,  as  a  rule,  in  a  very  rudimentary 
condition ;  in  fact,  so  rudimentary  that  it  is  difficult  to  distinguish 
the  ovaries  of  two  flowers  that  develop  into  quite  different  fruits. 
In  some  instances  it  is  said  that,  notwithstanding  the  subsequent 
changes,  each  cell  of  the  fruit  is  already  indicated  in  the  ovary. 
The  ovary  possesses  an  outer  and  an  inner  epidermis;  the  outer 
is  provided  with  stomata  and. may  also  possess  hairs;  the  inner 
may  also  have  stomata  and  after  fertilization  may  develop  secre- 
tion hairs,  as  in  the  orange.  Between  the  epidermal  layers  occur 
thin-walled  parenchyma  cells  which  contain  leucoplastids  and 
chloroplastids,  and  in  which  the  fibrovascular  bundles  are  dis- 
tributed, these  being  usually  simple,  or  complex,  as  in  the  pea. 
The  number  of  fibrovascular  bundles  is  more  or  less  dependent 


MORPHOLOGY  OF  HIGHER  PLANTS. 


407 


FIG.  235.  Inner  morphology  of  flower  of  Primula  officinalis:  A,  papillae  on  stigma 
of  flower  with  long  styles;  B,  papillae  from  stigma  of  flower  with  short  styles;  C,  sec- 
tion through  petals  showing  papillose  epidermal  layers  and  branching  cells  of  mesophyll ; 
D,  section  through  corolla  tube  showing  glandular  hairs  on  epidermis;  E,  surface  view  of 
epidermal  cells  of  petals,  those  of  the  corolla  tube  being  elongated  and  shown  on  the  left, 
while  those  of  the  outspreading  petals  are  polygonal  and  striated  from  the  folds  in  the 
papillae;  F,  a  pollen  grain. — Redrawn  by  Haase  from  drawing  of  Hans  Kramer  in  Ber. 
d.  d.  pharm.  Ges.,  1907,  p.  352. 


4o8  A  TEXT-BOOK  OF  BOTANY. 

upon  the  number  of  carpels  that  make  up  the  gynaecium;  as  a 
rule,  there  is  a  strong  fibrovascular  bundle  which  corresponds  to 
the  mid-vein  of  each  carpel. 

The  PLACENTA  is  a  development  from  the  inner  epidermis.  It 
is  traversed  by  a  fibrovascular  bundle  from  which  branches  are 
given  off  to  the  individual  ovules ;  it  may  have  a  conducting  tissue 
similar  to  that  found  in  the  style,  and  in  some  cases  the  epidermis 
of  the  stalk  of  the  ovule  may  be  developed  to  a  stigma-epithel. 

The  OVULE  not  only  possesses  a  distinct  form  as  already  given, 
but  the  internal  structure,  by  reason  of  the  changes  associated  with 
fertilization,  is  more  or  less  characteristic  for  certain  species  and 
genera.  It  has  an  epidermal  layer,  the  outer  walls  of  which  are 
more  or  less  cutinized,  and  it  consists  for  the  most  part  of  paren- 
chyma cells  rich  in  protoplasm  and  food-materials ;  in  addition  the 
embryo-sac  contains  a  number  of  nuclei.  The  stalk  and  raphe  are 
connected  with  the  placenta  by  means  of  a  fibrovascular  bundle. 

The  NECTAR  may  be  secreted  by  certain  of  the  epidermal  cells 
of  various  parts  of  the  flower;  these  may  resemble  the  ordinary 
epidermal  cells  or  they  may  be  modified  to  papillae,  as  in  the 
spurred  stamens  of  the  violets,  or  to  hair-like  processes,  as  in 
malva.  The  cells  which  secrete  nectar  constitute  the  "  nectar- 
apparatus,"  and  the  walls  are  usually  thin  and  more  or  less  cutin- 
ized. The  nectar-apparatus  is  found  more  generally  upon  some 
part  of  the  stamen,  but  the  sepals  and  petals  are  not  infrequently 
saccate  or  spurred,  which  adapts  them  for  holding  the  nectar. 

V.     OUTER    MORPHOLOGY    OF   THE    FRUIT. 

After  the  fertilization  of  the  ovule  or  ovules,  the  parts  of  the 
flower  that  play  no  further  part  either  in  protecting  the  seed  or 
aiding  in  its  dispersal  soon  wither  and  are  cast  off ;  in  most  flowers 
the  petals  lose  their  color  and,  together  with  the  stamens,  style, 
and  stigma,  wither  and  fall  away  shortly  after  fertilization.  The 
stigma  may,  however,  persist,  as  in  the  poppy ;  the  style  may  like- 
wise remain,  as  in  Ranunculus,  or  even  continue  to  grow  or 
lengthen,  as  in  Taraxacum;  in  other  cases  the  calyx  persists,  as 
in  orange  and  belladonna ;  in  still  other  cases  the  torus  may  be- 
come fleshy  and  form  a  part  of  the  fruit,  as  in  pimenta  and  apple. 
The  fruit  may  consist,  therefore,  not  only  of  the  ripened  pistil, 


MORPHOLOGY  OF  HIGHER  PLANTS.     409 


FIG.  236.  Different  types  of  fruits.  A,  silique  of  mustard  showing  the  separation  of 
the  two  valves  leaving  the  seeds  attached  to  the  central  axis;  B,  spinous  capsule  of  Stra- 
monium showing  septifragal  dehiscence  into  four  valves,  the  capsule  being  strictly  2- 
locular  but  apparently  4-locular  owing  to  the  formation  of  false  dissepiments;  C,  s-valved 
capsule  of  Geranium  in  which  the  carpels  become  detached  from  one  another  and  roll  up- 
wards remaining  attached  to  the  beak-like  compound  style;  D,  capsule  of  Hyoscyamus 
showing  transverse  dehiscence  by  means  of  a  lid  (i)  and  the  two  loculi  containing  numerous 
small  seeds;  E,  fruit  of  strawberry  showing  fleshy  torus  and  numerous  embedded  akenes; 
F,  silicula  of  shepherd's-purse  showing  seeds  attached  to  central  axis  and  longitudinal 
dehiscence  of  the  valves  which  remain  attached  below;  G,  fruit  of  rose,  so-called  rose  "hip," 
the  akenes  being  enclosed  by  the  hollow  oval  torus  which  shows  remains  of  calyx  at  the 
apex;  H,  multiple  fruit  of  mulberry  composed  of  small  drupes,  the  pulpy  portion  of  each 
consisting  of  the  fleshy  perianth. — Adapted  from  Warming. 

but  also  of  other  parts  of  the  flower  and  torus  which  persist  or 
develop  with  it. 


4io 


A  TEXT-BOOK  OF  BOTANY. 


The  wall  of  the  fruit  is  called  the  PERICARP,  and,  like  the  leaf, 
it  consists  of  three  distinct  layers,  viz. :  ( i )  the  outer  layer  corre- 
sponding to  the  outer  epidermis  of  the  ovary  is  called  the  EPICARP 
or  EXOCARP;  (2)  the  inner  layer  corresponding  to  the  inner 
epidermis  of  the  ovary  is  called  the  ENDOCARP,  or,  from  the  fact 
that  it  is  sometimes  hard  and  stone-like,  it  is  called  the  PUTAMEN, 
as  in  the  prune;  and  (3)  the  middle  layer  situated  between  the 
epicarp  and  endocarp  is  called  the  MESOCARP  ;  and  from  the  fact 
that  it  is  sometimes  succulent  or  fleshy,  as  in  the  prune,  it  is  also 
called  the  SARCOCARP. 

There  are  a  number  of  distinctive  and  descriptive  names  applied 
to  fruits.  Some  of  the  more  imoortant  are  as  follows : 


FIG.  237.  A,  transverse  section  of  colocynth  showing  seeds  (s)  borne  on  parietal 
placentas;  B,  transverse  section  of  fruit  of  Ricinus  communis  showing  septicidal  dehis- 
cence  of  capsule,  the  seeds  (s)  being  borne  on  axial  placentas;  C,  transverse  section  of  card- 
amom showing  loculicidal  dehiscence,  the  seeds  (s),  as  in  B,  being  borne  on  axial  placentas. 

An  Achene  is  a  non-fleshy,  or  so-called  dry,  unilocular  and 
one-seeded,  indehiscent  fruit,  in  which  the  pericarp  is  more  or  less 
firm,  and  may  or  may  not  be  united  with  the  seed.  Achenes  may 
be  inferior,  as  in  the  Composite  (Fig.  227),  where  they  develop 
from  inferior  ovaries,  being  frequently  surmounted  by  the  pappus 
or  calyx;  or  half  inferior,  as  in  the  rose  (Fig.  236,  G),  where  they 
develop  from  half  inferior  ovaries ;  or  superior,  as  in  the  buttercup 
(Fig.  223,  D). 

A  Berry  is  a  fleshy,  indehiscent  fruit,  the  seeds  of  which 
are  embedded  in  the  sarcocarp;  berries  are  superior  when  they 
develop  free  from  the  torus,  as  in  belladonna  (Fig.  239),  capsi- 
cum, grape,  etc.,  and  inferior  when  the  torus  forms  a  part  of 
the  fruit,  as  in  banana,  cranberry  (Fig.  244),  and  gooseberry 
(Fig.  245). 


MORPHOLOGY  OF  HIGHER  PLANTS. 


411 


A  Capsule  is  a  dry,  dehiscent  fruit,  consisting  of  two  or  more 
united  carpels.  Dehiscence  in  capsules  may  occur  in  five  different 
ways:  In  the  castor-bean  (Fig.  237,  B)  the  carpels  separate  from 
each  other  along  the  walls  or  septa  (dissepiments),  the  seeds  being 
discharged  along  the  ventral  suture  of  the  separated  carpels,  and 
this  mode  of  dehiscence  is  called  SEPTICIDAL.  In  mustard  (Fig. 


FIG.  238.  Capsules  of  poppy  (Papaver  somniferum) ,  whole  and  in  transverse  and 
longitudinal  sections,  showing  dissepiments  and  remains  of  radiate  stigmas  at  the  apex, 
which  are  porous  and  through  which  the  seeds  are  discharged,  i,  French  capsules;  2, 
German  capsules. 

236,  A )  the  dissepiments  remain  intact  and  dehiscence  occurs  along 
the  margin  of  the  capsule,  and  is  therefore  called  MARGINICIDAL  ; 
but  as  the  partial  carpels  (or  valves,  as  they  are  termed)  separate 
from  the  walls  or  septa,  the  dehiscence  is  also  known  as  SEPTI- 
FRAGAL.  In  cardamom  (Fig.  237,  Q  the  septa  as  well  as  valves 
are  united,  and  at  maturity  the  latter  separate  and  dehisce  at  points 
in  the  margin  corresponding  to  the  mid-vein  of  the  carpel,  and 


412 


A  TEXT-BOOK  OF  BOTANY. 


this   form  of  dehiscence  is  known  as  LOCULTCTDAL.     In  poppy 
capsules  (Fig.  238)  there  are  a  few  openings  beneath  the  united 


PIG.  239.  Several  forms  of  fruits:  A,  branch  of  Apocynum  androscemifolium  showing 
numerous  flowers  and  a  single  fruit  with  2  long,  slender  follicles.  Comparative  size  of  follicles 
in  A.  androscemifolium  (B),  and  A.  cannabinum  (C).  Branch  of  Solatium  carolinense 
showing  a  number  of  small  superior  berries  (D).  Pyxis  of  Scopolia  carniolica  showing 
slightly  lobed  calyx  and  upper  portion  of  fruit  (E).  Pyxis  in  Hyoscyamus  niger  showing 
calyx  lobes  extending  much  above  the  fruit  (F).  Berry  of  Atropa  Belladonna  cut  trans- 
versely and  showing  the  numerous  small  seeds  (G).  Young  spinose  capsule  of  Datura 
Stramonium  (H). 

stigmas  through  which  the  seeds  are  expelled,  and  this  form  of 
dehiscence  is  known  as  POROUS.     In  hyoscyamus  (Fig.  236,  D)  a 


MORPHOLOGY  OF  HIGHER  PLANTS. 


413 


portion  of  the  capsule  comes  off  from  the  remainder  like  a  lid, 
and  this  form  of  dehiscence  being  circular  or  transverse  to  the 

1st 
II  ^L*  ^^  qst 


Alb 


FIG.  240.  The  fruit  of  the  cocoanut  palm  (Cocos  nueifera):  I,  ripe  cocoanut  fruit 
showing  lower  part  of  axis  forming  the  stem  (S),  upper  end  of  axil  with  scars  of  male  flowers 
(A),  epicarp  (Ep),  mesocarp  (M)  with  fibers,  endocarp  or  hard  shell  (E),  portion  of  testa 
adhering  to  endosperm  (T),  endosperm  surrounding  cavity  of  nut  (Alb)  and  germinating 
eye  (K);  II,  longitudinal-radial  section  of  endocarp  through  the  stone  cells  and  edge  of 
bundle  showing  transversely  elongated  and  isodiametric  stone  cells  (qst),  longitudinally 
elongated  stone  cells  (ist),  thick-walled  porous  cells  (f),  pitted  tracheae  (g)  and  spiral 
tracheae  (sp);  III,  longitudinal  section  of  a  large  (mesocarp)  fiber  showing  stegmata  (ste), 
silicious  body  (Si),  bast  fibers  (f),  tracheids  with  small  pits  (t),  tracheids  with  large  pits 
(tO,  spiral  tracheae  (sp),  reticulated  tracheae  (r),  scalariform  tracheae  (sc),  sieve  tube  (s) 
and  cambiform  cells  (c  and  c')- — After  Winton. 

sutures  of  the  carpel,  it  is  called  CIRCUMCISSILE.     A  capsule  of 
this  kind  is  known  as  a  Pyxis  or  Pyxidium. 


A  TEXT-BOOK  OF  BOTANY. 


—  mes 


st 


VI 


FIG.  241.  Fruit  of  the  huckleberry  (Gaylussacia  resinosa):  I,  fruit  seen  from  above; 
II,  transverse  section  of  fruit;  III,  stone;  IV,  transverse  section  of  stone  showing  endocarp 
(End),  testa  (S),  endosperm  (E)  and  embryo  (em);  V,  transverse  section  of  outer  portion 
of  the  pericarp  showing  epicarp  (epi),  hypoderm  (hy),  mesocarp  (mes)  and  stone  cells  (st) ; 
VI,  transverse  section  of  endocarp  and  seed  showing  large  isodiametric  stone  cells  (End), 
narrow  longitudinally  extended  fibers  (If),  testa  (S),  hyaline  layer  or  nucellus  (N)  and 
endosperm  (E). — After  Winton. 


MORPHOLOGY  OF  HIGHER  PLANTS. 

R, 


415 


FlG.  242.  Cultivated  strawberry  (Fragaria  chiloensis):  I,  Compound  fruit  showing 
fleshy  receptacle  bearing  the  achenes  in  deep  depressions;  II,  isolated  achene;  III,  achene 
showing  style  (Sty),  stigma  (Sti)  and  connecting  bundle  (B);  IV,  achene  in  transverse 
section,  pericarp  (F),  testa  (S).raphe  (R),  endosperm  (E)  and  embryo  (Em);  V,  receptacle 
in  surface  view  showing  epidermis  (Ep),  with  hair  (h),  and  stoma  (sto);  hypoderm  (hy) 
and  sphero-crystals  (k) ;  VI,  achene  in  transverse  section  showing  pericarp  (F)  consisting 
of  epicarp  (epi),  mesocarp  (mes), spiral  vessels  (sp),  crystal  layer  (k) ,  outer  endocarp  (If) 
with  longitudinally  extended  fibers  and  inner  endocarp  (qf)  with  transversely  extended 
fibers;  testa  (S)  consisting  of  epidermis  (ep)  with  reticulated  cells,  elongated  brown  cells 
(br),  hyaline  layer  or  nucellus  (N)  and  endosperm  (E)  consisting  of  a  single  layer  of  aleurone 
grains;  VII,  style  and  stigma. — After  Winton. 


4i6 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  243.  Red  Raspberry  (Rubus  Idaus):  I,  Compound  fruit  consisting  of  a  number 
of  drupelets  crowded  together  on  the  top  and  sides  of  the  receptacle;  II,  transverse  section 
of  a  drupelet  showing"epicarp  (epi),  hypoderm  (Hy),  mesocarp  (Mes),  outer  endocarp  (F), 
inner  endocarp  (F'),  testa  (S),  raphe  (R),  endosperm  (E),  and  embryo  (Em);  III,  stone 
including  endocarp  and  seed;  IV,  stone  somewhat  magnified;  V,  style  and  stigma;  VI, 
surface  section  of  epicarp  showing  straight  hair  (h'),  sinuous  hairs  (h)  and  stoma  (sto); 
VII,  transverse  section  of  endocarp  and  seed  showing  endocarp  (End)  consisting  of  longi- 
tudinally extended  fibers  (If),  transversely  extended  fibers  (qf),  testa  (S)  consisting  of 
epidermis  (ep),  parenchyma  or  nutritive  layer  (p),  and  inner  epidermis  (iep);  hyaline 
layer  or  nucellus  (N),  endosperm  (E)  with  aleurone  grains  (k). — After  Winton. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


A  Caryopsis,  or  Grain,  is  an  indehiscent,  non-fleshy  fruit 
possessing  a  thin  pericarp,  which  is  closely  adherent  to  the  thin 
seed-coats,  as  in  wheat,  corn,  and  other  Gramineae  (Figs. 
255,256). 


i— <•) 


— -E 


VII 


FIG.  244.  The  fruit  of  the  cultivated  cranberry  (Vaccinium  macrocarpon):  I,  berry 
seen  from  above;  II,  transverse  section  of  berry;  III,  single  seed;.  IV,  transverse  section 
of  seed  showing  outer  epidermis  (S),  inner  layer  of  seed-coat  (S'),  raphe  (R),  endosperm  (E) 
and  embryo  (Em);  V,  surface  section  of  endocarp  with  stoma;  VI,  seed  in  transverse  sec- 
tion showing  epidermis  of  seed-coat  (ep)  with  sclerenchymatized  and  mucilaginous  layers, 
inner  layer  of  seed-coat  (m)  and  endosperm  (E);  VII,  surface  section  of  epidermis  of  seed- 
coat. — After  Winton. 

A  Cremocarp  is  a  dry,  indehiscent  fruit  which  consists  of 
two  inferior  achenes,  known  as  MERICARPS;  these  are  separated 
from  each  other  by  means  of  a  stalk  known  as  a  CARPOPHORE. 
27 


418 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  245.  The  fruit  of  the  American  Gooseberry  (Ribes  oxyacanthoides}:  I,  whole 
fruit;  II,  transverse  section  of  fruit  with  seeds;  III,  seeds  deprived  of  gelatinous  coat; 
IV,  floral  parts;  V,  surface  section  of  epidermis  from  margin  of  calyx  with  hairs;  VI,  surface 
section  of  epidermis  from  throat  of  calyx  with  hair. — After  Winton. 

This  fruit  is  characteristic  of  the  Umbellifera.     (Consult  Volume 
II  for  pharmacognosy  of  medicinal  umbelliferous  fruits.) 

A  Drupe  is  a  fleshy,  indehiscent  fruit  with  a  more  or  less 
succulent  and  well-developed  sarcocarp  and  an  indurated  endo- 


MORPHOLOGY  OF  HIGHER  PLANTS.  419 

carp.  Drupes  are  superior  when  they  are  free  from  the  torus,  as 
in  prune ;  inferior  when  the  torus  forms  a  part  of  the  fruit,  as 
in  pimenta.  Drupes  are  also  spoken  of  as  "  dry  "  when  the  sarco- 
carp  is  less  succulent,  as  in  Rhus  glabra,  or  when  they  are  col- 
lected unripe,  as  in  pepper,  pimenta,  and  cubeb.  The  fruits  of  the 
raspberry  and  blackberry  consist  of  a  collection  of  little  drupes, 
the  whole  being  known  as  an  ET^RIO.  In  the  blackberry  the 
drupelets  cohere  with  the  fleshy  torus,  while  in  the  raspberry  the 
drupelets  cohere  with  one  another,  forming  a  cap  which  is  sepa- 
rable from  the  cone-shaped  torus.  If  the  drupelets  of  the  rasp- 
berry are  examined  closely  it  will  be  found  (Fig.  243)  that  each 
has  from  4  to  7  facets  on  the  sides  formed  by  the  pressure  of  the 
adjoining  drupelets.  These  facets  are  usually  slightly  convex  or 
concave.  Tschierske  states  that  the  individuals  cling  together, 
first,  because  of  the  closely-fitting  adjoining  facets,  the  slightly 
convex  surface  of  one  fitting  into  a  corresponding  concave  surface 
of  another;  and,  second,  because  of  the  interlocking  of  the  sinuous 
hairs. 

A  Follicle  is  a  dry,  dehiscent  fruit  which  consists  of  one 
or  more  separate  carpels,  the  dehiscence  being  usually  along  the 
ventral  suture  (Fig.  239)  ;  in  Delphinium  the  carpels  are  single ;  in 
aconite  from  3  to  5,  and  in  star-anise  (Illicium)  from  7  to  8;  in 
magnolia  the  carpels  are  numerous,  forming  a  kind  of  succulent 
cone,  and  dehisce  along  the  dorsal  suture. 

A  Galbalus  is  a  berry-like  fruit,  formed  by  the  coalescence 
of  fleshy,  open  scales,  as  in  juniper  (Fig.  75). 

Hesperidium. — The  fleshy,  indehiscent,  superior  fruit  of  citrus, 
as  lemon  and  orange,  is  known  as  a  hesperidium.  The  pericarp 
is  more  or  less  coriaceous,  and  from  the  inner  walls  secretion  hairs 
develop,  which  contain  sugar  and  an  acid  cell-sap,  these  consti- 
tuting the  fleshy  portion  in  which  the  seeds  are  embedded. 

A  Legume  is  an  elongated,  monocarpellary,  usually  dry, 
dehiscent  fruit,  in  which  dehiscence  takes  place  along  both  sutures, 
the  carpel  thus  dividing  into  two  halves,  or  valves,  as  in  the  garden 
pea  (Pisum)  and  other  members  of  the  Leguminosse  (Fig.  231). 
In  some  cases  legumes  are  jointed  or  articulated  and  indehiscent, 
breaking  up  at  maturity  into  a  number  of  parts  which  are  dis- 
persed in  much  the  same  manner  as  samara-fruits,  as  in  Meibomia. 


420  A  TEXT-BOOK  OF  BOTANY. 

Legumes  may  be  not  only  indehiscent  but  fleshy,  as  in  Cassia 
fistula. 

A  Nut  is  an  achene-like  fruit,  the  pericarp  o'f  which  is  more 
or  less  indurated.  Nuts  are  sometimes  subtended  (as  in  acorns) 
or  enclosed  (as  in  chestnuts)  by  a  kind  of  involucre,  forming 
what  is  technically  known  as  a  cupule ;  and  a  fruit  consisting  of  a 
nut  and  cupule  is  known  as  a  GLANS.  The  achene-like  fruit  of 
the  Labiatae  is  spoken  of  as  a  Nutlet. 

A  Pepo  is  an  inferior  berry,  in  which  the  placentas  have 
become  developed  into  succulent  layers,  as  in  the  watermelon, 
cucumber,  and  colocynth. 

A  Pod  is  a  general  term  used  to  designate  all  dry,  dehiscent, 
apocarpous,  or  syncarpous  fruits,  as  capsules,  follicles,  and 
legumes. 

A  Pome  is  an  indehiscent,  half-inferior,  fleshy,  syncarpous 
fruit,  as  in  the  apple.  The  carpels  constitute  the  core,  and  the 
fleshy  part  is  developed  from  the  torus. 

A  Samara  is  a  winged,  achene-like  fruit.  The  winged  ap- 
pendage may  be  at  the  apex,  as  in  white  ash,  or  around  the  edge,  as 
in  elm.  Two  samaras  may  be  united  into  one  fruit,  which  is  called 
a  "  double  samara,"  as  in  maple. 

A  Silique  is  a  narrow,  elongated,  2-valved  capsule  which  is 
separated  by  the  formation  of  a  false  dissepiment  into  2  locules,  as 
in  the  Cruciferse  (Fig.  236,  A). 

A  Sorosis  is  a  fleshy  fruit  resulting  from  the  aggregation 
of  the  carpels  of  several  flowers,  as  in  mulberry  (Fig.  236,  //) 
and  pineapple. 

A  Strobile  or  cone  is  a  scaly  fruit,  at  the  base  of  each  scale 
of  which  there  is  either  a  seed,  as  in  the  Pinacece,  or  an  achene-like 
body,  as  in  hop. 

A  Syconium  consists  of  a  succulent  hollow  torus,  which  en- 
closes a  number  of  achene-like  bodies,  as  in  the  fig  (Ficus). 

An  Utricle  is  an  inferior  achene  with  a  thin  and  loose  pericarp, 
as  in  Chenopodium. 

Classification  of  Fruits. — More  or  less  artificial  classifications 
of  fruits  have  been  made.  They  may  be  grouped  either  according 
to  structure  or  according  to  their  manner  of  protection  or  dispersal, 
the  following  classification  being  based  on  the  structure : 


MORPHOLOGY  OF  HIGHER  PLANTS. 


421 


From  a  number  of  flowers. 


From  a  single 
flower 


A.  With  a  compound  pistil. 


a.  Indehlscent 


Dry.... 


Fleshy , 


b.  Dehiscent ]  Dry 


Strobile  or  Cone 

Sorosis 

Syconium 
(Achene 

Caryopsis 

Cremocarp 

Nut 

Samara 

Utricle 

Berry 

Drupe 

Etaerio 

Hesperidium 

Pepo 

Pome 
f  Capsule 
1  Follicle 


B,  With  a  simple  pistil 


a.  Indehiscent .  .  .  \  Fleshy  .  .  \  Drupe 


b.   Dehiscent \  Dry 


[Follicle 
I  Legume 


THE    INNER    STRUCTURE    OF    FRUITS. 

The  inner  structure  of  fruits  is  quite  variable  and  it  is  difficult 
to  treat  of  this  in  a  general  way.  In  the  simplest  fruits  there  are 
three  distinct  layers,  as  in  the  capsule  of  cardamom,  in  which 
there  is  an  outer  epidermis  of  isodiametric  or  polygonal  cells, 
an  inner  epidermis  of  more  or  less  obliterated  and  elongated  cells, 
between  which  is  a  thin-walled  parenchyma  traversed  by  a  number 
of  fib ro vascular  bundles. 

In  some  cases  the  other  epidermis  contains  numerous  stomata, 
as  in  poppy  capsules,  or  is  developed  into  hairs  and  other  out- 
growths or  appendages,  as  in  anise,  arnica,  sumach  (Fig.  148), 
and  raspberry  (Fig.  243). 

The  inner  epidermis  may  also  contain  stomata,  as  in  the  poppy, 
or  be  developed  into  hairs,  as  in  vanilla  and  orange,  or  more  or  less 
obliterated,  as  in  achene-like  fruits,  or  modified  to  sclerenchy- 
matous  elements,  as  in  drupes. 


422 


A  TEXT-BOOK  OF  BOTANY. 


The  middle  layer,  which  is  composed  of  parenchyma,  may  con- 
tain protoplasm,  starch,  sugars,  calcium  oxalate,  coloring  princi- 
ples, alkaloids  and  other  principles,  and  it  may  also  have  oil-secre- 
tion cells,  as  in  cubeb  and  pepper,  or  oil-secretion  canals,  as  in 
^orange  (Fig.  121)  and  the  fruits  of  the  Umbelliferae,  in  the  latter 


FIG.  246.  Rhamnus  cathartica.  A,  cross-section  through  wall  of  the  pericarp.  E,  epi- 
carp;  F,  sarcocarp;  H,  endocarp;  e,  epidermis;  o,  calcium  oxalate  in  cells  of  hypodermis;  p, 
parenchyma;  h,  secretion  cells  containing  a  substance  which  is  insoluble  in  alcohol  or  chloral 
solutions,  soluble  in  solutions  of  potassium  hydroxide,  and  colored  reddish  brown  or  green- 
ish with  ferric  chloride  solutions;  c,  calcium  oxalate  cells  of  endocarp;  w,  sclerotic  cells;  f, 
stereome  cells.  B,  cross-section  of  entire  fruit,  showing  one  seed;  E,  F.  H,  g,  f,  w,  as  in  A; 
S,  seed-coat;  S1,  outer  wall  of  seed-coat;  End,  endosperm;  c,  cotyledons;  g,  vascular  bundle. 
C,  cross-section  of  a  seed:  S1,  S2,  S3,  different  layers  of  the  seed-coat;  R,  vascular  bundle  of 
raphe;  t,  position  of  vessels  of  mestome  strand;  g,  mestome  strand;  Rf,  cleft  in  which  raphe 
is  situated;  End,  endosperm;  C  cotyledons;  Sv,  cells  with  thick  walls;Sp,parenchymatous 
cells. — After  Meyer. 

of  which  they  are  known  as  vittse  (see  Volume  II)  ;  milk  vessels 
sometimes  occur,  as  in  poppy;  a  collenchymatous  layer  is  some- 
times developed  beneath  the  epidermis,  as  in  capsicum;  in  some 
cases  sclerenchymatous  cells  may  be  present,  as  in  pimenta  and 
cubeb  (Fig.  135)  ;  and  in  still  other  instances  the  entire  pericarp 
may  be  made  up  of  stone  cells,  as  in  the  nuts. 


MORPHOLOGY  OF  HIGHER  PLANTS. 


VI.     THE   OUTER   MORPHOLOGY    OF   THE   SEED. 


423 


The  seed  may  be  defined  as  the  fertilized  and  developed  ovule. 
The  seeds  of  different  fruits  vary  in  number  as  well  as  in  size 


FIG.  247.  Transverse  (I)  and  longitudinal  (II)  sections  of  oat  grain  (Avena  saliva): 
i,  2,  cells  of  pericarp;  3,  seed-coat;  4,  remains  of  perisperm;  5,  cells  containing  gluten; 
7,  endosperm  cells  containing  considerable  proteins  and  some  starch;  6,  endosperm  cells 
With  polygonal  compound  starch  grains;  8,  fibrovascular  bundle  of  the  pericarp. — After  Harz. 

and  shape.  In  form  they  correspond  to  the  ovules ;  in  size  they 
vary  from  about  0.600  mm.,  as  in  lobelia,  belladonna,  etc.,  to  10  or 
15  centimeters  in  diameter,  as  in  the  cocoanut  palm.  Seldom  are 


424 


A  TEXT-BOOK  OF  BOTANY. 


all  of  the  ovules  of  the  pistil  fertilized,  hence  the  number  of  seeds 
is  usually  less  than  the  number  of  ovules. 

Structure  of  Seed. — After  the  fertilization  of  the  egg-cell 
certain  changes  take  place  in  the  embryo-sac:  At  one  end  the 
developing  embryo  is  attached  to  the  wall  by  a  short  stalk  or 
suspensor  (Fig.  82)  ;  the  nuclei,  lying  in  a  mass  of  cytoplasm 

A" 


FIG.  248.  Citrullus  Colocynthis.  A,  seed:  a,  in  longitudinal  section,  and  b,  surface  view; 
S,  deep  clefts  or  fissures;  m,  micropyle;  g,  hilum;  w,  radicle;  c,  cotyledons.  B,  parenchyma 
cells  of  ripe  fruit  showing  simple  pores,  the  walls  are  colored  blue  with  chlor-zinc-iodide. 
C,  longitudinal  section  of  wall  of  pericarp  of  ripe  fruit  showing  e,  epidermis;  p,  parenchyma; 
Sc,  sclerotic  cells  which  gradually  pass  into  a  thick-walled  parenchyma  consisting  of  small 
cells  (p');  g.  spiral  vessels;  P,  isodiametric,  porous  parenchyma  cells,  containing  air  and  of 
which  the  fruit  for  the  most  part  consists.  D,  cross-section  of  seed-coat  showing,  G,  an 
outer  layer  which  is  more  or  less  easily  separable  from  the  rest  of  the  seed  and  the  walls  of 
which  are  somewhat  mucilaginous;  E,  epidermis  of  palisade-like  cells;  Sc,  sclerotic  cells;  PI, 
a  layer  of  tabular  cells  with  undulate  walls;  T,  a  layer  of  small  somewhat  branching  cells, 
the  walls  of  which  are  not  strongly  thickened  and  either  porous  or  reticulate;  P,  several 
layers  of  parenchyma  and  the  collapsed  epidermis;  Pe,  perisperm;  En,  endosperm.  E, 
tangential  section  of  tabular  sclerotic  cells  of  seed-coat  shown  in  PI  in  Fig.  D. — After  Meyer. 

around  the  wall  of  the  embryo-sac,  divide  and  re-divide;  the  large 
vacuole  in  the  center  becomes  filled  with  a  watery  or  milky  fluid, 
and  later  the  nuclei,  with  portions  of  the  cytoplasm,  may  be 
enclosed  by  a  cellulose  wall  and  become  permanent  cells,  in  which 
the  embryo  is  embedded.  Likewise  in  the  nucellus,  changes  are 
also  taking  place ;  the  cells  are  found  to  be  dividing,  and  storing 
starch,  oil,  aleurone,  and  other  food  materials,  like  the  cells  of  the 


MORPHOLOGY  OF  HIGHER  PLANTS.     425 

embryo-sac.  The  cells  in  which  these  materials  are  stored  are 
known  as  reserve  cells,  and  in  the  nucellus  they  constitute  the 
PERISPERM,  while  those  formed  in  the  embryo-sac  make  up  the 
ENDOSPERM.  Usually  the  endosperm  of  seeds  is  prominently  de- 
veloped, while  the  perisperm  occurs  as  a  thin  layer ;  in  some  seeds, 
however,  the  endosperm  and  perisperm  are  both  well  developed. 
In  some  instances  the  embryo  may  not  fill  the  embryo-sac,  as  in 
cocoanut,  and  sometimes,  as  in  the  almond,  both  of  the  reserve 
layers  are  consumed  in  the  development  of  the  embryo,  when  the 
seed  is  said  to  be  without  endosperm  (Fig.  248). 

The  perisperm  and  endosperm  are  sometimes  spoken  of  to- 
gether as  the  albumen  of  the  seed,  but  as  the  cells  comprised  in 
these  layers  contain  not  only  protoplasmic  contents  and  aleurone 
grains,  but  starches,  oils,  and  other  substances,  the  term  is  mis- 
leading. On  this  basis,  seeds  containing  either  endosperm  or 
perisperm,  or  both,  have  been  designated  as  albuminous,  but  on 
.account  of  these  layers  containing  larger  proportions  of  other, 
(substances  than  proteins  it  would  be  better  to  speak  of  them  as 

RESERVE  LAYERS    (FigS.  247,  250). 

While  these  changes  in  the  nucellus  and  embryo-sac  have  been 
going  on  there  have  been  equally  great  changes  in  the  coats  of 
the  ovules,  which  develop  into  the  seed-coats.  In  the  seed  the 
two  coats  are  generally  readily  distinguishable.  The  inner,  as 
in  Ricinus,  Pepo,  etc.,  is  thin,  light  in  color,  of  a  delicate  structure, 
and  is  known  as  the  TEGMEN  ;  the  outer  is  more  or  less  thickened, 
of  a  darker  color  and  firmer  in  structure,  and  is  known  as  the 
TESTA.  In  some  instances  the  perisperm,  or  both  perisperm  and 
endosperm,  may  be  reduced  to  a  thin  layer  when  it  is  considered 
to  form  a  part  of  the  seed-coat,  as  in  mustard.  In  other  cases  the 
two  coats  are  so  closely  united  that  they  are  not  easily  distin- 
guished, as  in  stramonium. 

The  terms  used  in  describing  the  kinds  of  ovules  (atropous, 
anatropous,  campylotropous,  etc.)  are  retained  in  the  description 
of  the  seeds ;  and  in  describing  the  different  parts  of  the  seed  some 
of  the  terms  which  were  applied  to  the  ovule  are  also  retained,  as 
chalaza  and  raphe ;  the  seed  when  ripe  usually  becomes  detached 
from  its  stalk,  and  the  resulting  scar  is  called  the  HILUM  ;  that 
part  of  the  seed  corresponding  to  the  foramen  of  the  ovule  is 
more  or  less  closed  and  is  known  as  the  MICROPYLE;  the  embryo 


426 


A  TEXT-BOOK  OF  DOT  ANY. 


develops  in  such  a  way  that  the  tip  of  the  young  root  always 
points  in  the  direction  of  the  micropyle. 

In  the  fully  developed  embryo  three  distinct  parts  may  be  dif- 
ferentiated (Fig.  161)  :  (i)  The  COTYLEDONS;  (2)  the  part  below 
the  cotyledons,  known  as  the  HYPOCOTYL,  the  apical  portion  of 
which  constitutes  the  young  root  or  RADICLE;-^)  the  part  above 


B 


pe 


FIG.  249.  Forms  of  embryo  and  distribution  of  endosperm  in  various  seeds  and 
fruits.  A,  Ricinus  seed:  car,  caruncle;  m,  micropyle;  e,  embryo.  B,  superior  drupe  of 
Piper:  per,  pericarp;  e,  endosperm;  p,  perisperm.  C,  spinach  fruit  and  D,  corn  cockle  seed 
(Agrostemma  Githago):  per,  pericarp;  t,  seed-coat;  h,  hilum;  p,  perisperm;  e,  endosperm 
c,  curved  embryo. — A,  C,  D,  after  Harz;  B,  after  Baillon. 

the  cotyledons,  known  as  the  EPICOTYL,  the  apex  of  which  con- 
sists of  a  more  or  less  developed  bud  spoken  of  as  the  PLUMULE. 
The  position  of  the  embryo  (Figs.  249,  250)  in  the  seed  varies 
somewhat :  in  most  seeds  it  lies  in  the  center,  as  in  strophanthus 
and  linum;  it  may,  however,  be  excentral,  as  in  colchicum  and 
nutmeg.  The  cotyledons  are  usually  situated  above  the  hypocotyl, 
but  in  the  Cruci ferae,  either  their  edges  lie  against  the  hypocotyl, 
as  in  the  mustards,  when  they  are  said  to  be  ACCUMBENT  or  con- 


MORPHOLOGY  OF  HIGHER  PLANTS.     427 

duplicate,  or  they  lie  so  that  the  back  of  one  is  against  the  hypo- 
cotyl,  as  in  Lepidium,  which  position  is  known  as  INCUMBENT. 

Externally,  the  seed-coats  vary  considerably ;  they  may  be 
nearly  smooth,  as  in  ricinus ;  finely  pitted,  as  in  the  mustards ; 
prominently  reticulate,  as  in  staphisagria ;  hairy,  as  in  cotton, 
strophanthus,  and  apocynum  (Fig.  251 )  ;  or  winged,  as  in  the  seeds 
of  the  catalpa.  There  are  also  a  number  of  other  appendages,  these 
having  received  special  names:  the  wart-like  development  at  the 
micropyle  or  hilum  of  some  seeds,  as  in  castor-bean  and  violet,  is 
known  as  the  CARUNCLE;  in  the  case  of  sanguinaria,  a  wing-like 
development  extends  along  the  raphe,  and  this  is  known  as  the 
STROPHIOLE  ;  in  some  cases  the  appendage  may  completely  envelop 
the  seed,  when  it  is  termed  an  ARILLUS  ;  when  such  an  envelope 
arises  at  or  near  the  micropyle  of  the  seed,  as  the  mace  in  nutmeg, 
it  is  known  as  a  "  false  arillus,"  or  ARILLODE. 

Seed  Dispersal. — Seeds  and  fruits  are  distributed  in  various 
ways,  and  so  are  often  found  growing  in  localities  far  from  their 
native  habitat.  In  some  instances  seeds  are  adapted  for  distribu- 
tion by  the  wind,  being  winged,  as  in  Paulownia,  Catalpa,  and 
Bignonia,  or  plumed  and  awned,  as  in  Strophanthus  Kombe, 
Asclepias,  and  Apocynum  (Fig.  251 ).  As  examples  of  fruits  hav- 
ing special  parts  which  aid  in  their  distribution  may  be  mentioned 
the  achene  of  Taraxacum  which  is  provided  with  a  pappus  (Fig. 
227),  the  bladder-like  pericarp  of  Chenopodium,  and  the  winged 
fruit  or  samara  of  maple.  The  hooked  or  barbed  appendages  on 
some  fruits  serve  to  attach  them  to  animals,  and  thus  they  may  be 
widely  distributed,  as  in  the  burdock  and  Spanish  needles  (Bidens 
bipinnata).  In  still  other  cases  fruits  may  be  carried  long  distances 
by  water  currents,  or  even  by  ocean  currents,  as  those  of  thej 
Double-cocoanut  palm  (Lodo'icea  sechellarum) ,  which  while 
native  of  the  Seychelles  Islands  is  now  found  on  many  of  the 
islands  in  the  Pacific  and  Indian  Oceans.  It  may  also  be  mentioned 
in  this  connection  that  a  number  of  fruits,  as  the  garden  balsam, 
castor-oil  plant,  violets  (pansy,  etc.),  Wistaria,  etc.,  are  elastically 
dehiscent  and  discharge  the  seeds  with  considerable  force. 

THE  INNER  STRUCTURE  OF  THE  SEED. 

The  SEED-COAT  usually  consists  of  from  two  to  six  layers  of 
cells:  (i)  an  outer  layer  or  so-called  epidermis,  (2)  a  layer  of 


428 


A  TEXT-BOOK  OF  BOTANY. 


sclerenchymatous  cells  or  stone  cells,  (3)  a  pigment  layer,  (4,  5) 
one  or  two  rows  of  parenchymatous  cells,  (6)  a  row  of  more  or 
less  obliterated  parenchyma  cells. 

The  EPIDERMAL  CELLS  vary  considerably  in  different  species 


D 


FIG.  250.  A. — Longitudinal  section  through  anatropous  seed  of  Knum:  R,  raphe;  SC, 
seed-coat;  M,  hilum;  H,  micropyle;  EN,  endosperm;  C,  cotyledon;  HY,  hypocotyl.  B. — 
Longitudinal  section  through  stramonium  seed:  SC,  seed-coat;  H,  micropyle;  M,  hilum; 
EN,  endosperm;  E,  curved  embryo.  C. — Transverse  section  through  endosperm  of  nux 
vomica  showing  thick-walled  parenchyma,  the  cells  containing  oil  and  protoplasm.  D. — 
Transverse  section  through  endosperm  of  seed  of  Ricinus  comrmtnis,  one  cell  filled  with 
aleurone  grains,  each  with  a  crystalloid  and  globoid,  and  another  in  which  the  aleurone 
grains  have  been  dissolved,  the  cytoplasm  and  nucleus  remaining. 

both  as  regards  the  form  of  the  cells  and  the  composition  of  the 
walls  (Fig.  136).  The  cells  may  be  more  or  less  isodiametric  in 
cross-section,  as  in  cardamom  (see  Vol.  II)  ;  elliptical,  as  in  almond 
(Fig.  136,  D)  ;  palisade-like,  as  in  Abrus  precatorius,  or  more  or 


MORPHOLOGY  OF  HIGHER  PLANTS.  429 

less  irregular,  as  in  Delphinium.  While  the  outer  and  side  walls 
are  usually  thickened,  in  hyoscyamus  (Fig.  251),  it  is  the  inner 
and  side  walls  which  are  thickened,  the  outer  wall  remaining  thin. 
The  outer  wall  may  be  in  part  modified  to  mucilage,  as  in  mustard 
and  flaxseed  (Fig.  119)  ;  or  to  non-glandular  hairs  which  consist 
either  of  cellulose,  as  in  cotton  (Fig.  139),  or  lignocellulose,  as 
in  nux  vomica  (Fig.  119). 

The  PERISPERM  and  ENDOSPERM   (Fig.  249)  consist  chiefly  of 
parenchyma  cells,  which  contain,  besides  protoplasm,  starch,  as 
A  B 


FIG.  251.  Seeds:  A,  of  Hyoscyamus  muticus  with  epidermal  cells  having  wavy,  thick- 
ened walls,  those  at  the  edge  are  seen  in  section  and  snowing  that  the  outer  wall  is  not 
thickened.  B,  of  Lobelia  inflata  showing  reticulate  seed-coat  composed  of  uniformly  thick- 
ened and  strongly  lignified  cells.  C,  of  Apocynum  cannabinum  with  numerous  long  i-celled 
hyaline  hairs. 

in  physostigma ;  oil,  as  in  flaxseed  and  cottonseed ;  aleurone  grains, 
as  in  ricinus  (Fig.  250);  glucosides,  as  in  almond;  alkaloids, 
as  in  stramonium.  The  walls  are  usually  thin,  but  may  in  some 
instances  be  considerably  thickened,  as  in  coffee,  colchicum,  and 
nux  vomica  (Fig.  135). 

The  embryo  consists  chiefly  of  parenchyma  cells  with  a  few 
fibrovascular  bundles:  the  cotyledons  may  be  thin  and  leaf-like, 
as  in  ricinus  and  nux  vomica,  or  thick  and  fleshy,  as  in  almond 
and  cola,  or  partly  developed,  as  in  strophanthus ;  the  hypocotyl 
is  usually  small,  but  in  the  Umbelliferae  it  is  as  large  as  the 
cotyledons. 


CHAPTER  IV. 

BOTANICAL  'NOMENCLATURE. 

LET  the  student  consult  the  various  manuals  on  Botany  and 
even  some  of  the  larger  authoritative  works  and  he  will  be  imme- 
diately impressed  that  there  is  more  or  less  confusion  concerning 
the  names  of  certain  plants.  For  instance,  in  looking  up  the 
botanical  origin  of  the  False  Solomon's  Seal,  one  author  will  give 
it  as  Smilacina  racemosa,  while  another  writer  will  use  the  name 
of  Vagnera  racemosa.  Again,  if  the  student  desires  to  use  the 
correct  family  name  he  will  be  confused  both  as  to  the  correct 
spelling  of  the  name  as  well  as  the  name  of  the  family  itself,  the 
Grass  Family  being  given  as  Graminacese  or  Gramineae ;  the 
Leguminosse  may  be  divided  into  the  Mimosacese,  Csesalpinacese 
and  Papilionaceae.  At  first  thought  it  might  seem  that  this  incon- 
sistency is  peculiar  to  botanical  science,  but  as  a  matter  of  fact 
we  find  the  same  difficulties  in  the  language  of  other  sciences. 
This  confusion  is  due  to  the  fact  that  up  until  now  there  has  not 
been  an  international  agreement  or  even  one  of  a  national  character 
regarding  the  rules  to  be  observed  in  botanical  nomenclature. 

"  For  many  decades  it  has  been  almost  universally  felt  that 
botanical  nomenclature  should  rest  in  a  general  way  on  the  prin- 
ciple of  priority  of  publication,  or,  in  other  words,  that  the  name 
of  a  plant  was  the  first  one  assigned  to  it.  Nearly  all  botanists  of 
note  have  readily  assented  to  this  general  idea,  but  great  difficulties 
have  arisen  regarding  the  precise  limitations  which  should  be 
imposed  upon  the  principle.  Thus,  botanists  of  past  generations, 
including  such  great  leaders  as  the  De  Candolles,  Bentham,  the 
Hookers,  Gray,  von  Martins,  Eichler,  Baillon,  and  others,  have 
followed  the  principle  of  priority,  yet  they  have  made  frequent 
exceptions  based  on  considerations  of  taste  and  convenience  as  well 
as  practicality." 

"  With  the  expansion  of  the  subject  the  difficulty  of  agreement 
on  these  exceptions  has  increased,  and  some  recent  writers  have 
been  disposed  at  times  to  criticise  rather  harshly  the  earlier  bot- 
anists for  making  any  exceptions  whatever.  It  should  be  noticed, 
430 


BOTANICAL  NOMENCLATURE.  431 

however,  that  even  the  more  strenuous  of  these  reformers  them- 
selves admit  certain  exceptions.  They  have  found  it  necessary,  for 
instance,  to  fix  initial  dates,  and  to  rule  out  certain  names  as  too 
vague  in  their  definition  or  too  uncouth  in  their  form  to  be 
accepted." 

"  Ideas  as  to  the  best  mode  of  establishing  rules  or  reaching 
a  general  agreement  regarding  the  necessary  exceptions  to  the  bald 
principle  of  priority  have  differed  widely  and  given  rise  to  lively 
controversy.  To  some  it  has  seemed  best  to  advise  an  ideal  system 
and  then,  without  much  reference  to  the  wishes  or  convenience 
of  their  colleagues,  to  apply  it  in  local  publication.  To  the  vast 
majority,  however,  it  has  been  clear  that  the  subject  was  a  broad 
one,  involving  much  mutual  sacrifice  before  the  now  divergent 
usages  at  different  botanical  centers  could  be  brought  into  har- 
mony. The  question  is  also  an  international  one,  requiring  the 
botanists  of  different  nations  to  attain  a  common  agreement.  For 
some  years  there  was  a  growing  desire  for  an  international  meet- 
ing of  representative  botanists  who  should  give  the  matter  of 
nomenclature  careful  consideration  and  come,  if  possible,  to 
some  agreement  on  the  fundamental  rules  to  be  followed.  This 
feeling  took  definite  form  in  the  year  1900,  when  preliminary 
sessions  of  such  a  gathering  were  held  in  connection  with  the 
Paris  Congress  of  Botanists.  At  this  meeting  a  bureau  was 
formed  for  the  organization  of  an  International  Botanical-  Con- 
gress to  be  held  at  Vienna  in  June,  1905."  This  congress  convened 
in  Vienna  and  was  attended  by  between  five  and  six  hundred  bota- 
nists, representing  the  leading  botanical  institutions  of  the  world. 
They  framed  international  rules  which  should  be  used  in  the 
botanical  nomenclature  of  vascular  plants,  and  a  complete  list 
of  these  will  be  found  in  Rhodora,  the  journal  of  the  New 
England  Botanical  Club,  for  March,  1907.  A  few  of  the  general 
considerations  and  leading  principles  will  be  mentioned,  however, 
in  order  that  the  student  may  have  some  understanding  of  the 
subject. 

According  to  the  Vienna  Congress,  the  prescriptions,  which 
should  govern  the  system  of  botanical  nomenclature,  are  divided 
into  (i)  principles,  (2)  rules,  and  (3)  recommendations. 

Among  the  principles  that  should  be  adhered  to  is  that  scientific 


432  A  TEXT-BOOK  OF  BOTANY. 

names  are  to  be  in  Latin  for  all  groups.  When  taken  from  another 
language,  a  Latin  termination  is  given  them,  except  in  cases 
sanctioned  by  custom.  If  translated  into  a  modern  language,  it  is 
desirable  that  they  should  preserve  as  great  a  resemblance  as 
possible  to  the  original  Latin  names. 

Among  the  rules  to  be  followed  in  designating  the  nature  and 
the  subordination  of  the  several  groups,  the  following  were 
adopted : 

Every  individual  plant  belongs  to  a  species  (species),  every 
species  to  a  genus  (genus),  every  genus  to  a  family  (familia), 
every  family  to  an  order  (ordo),  every  order  to  a  class  (classis), 
every  class  to  a  division  (divisio).  In  a  number  of  species  varie- 
ties and  forms  are  also  distinguished.  In  some  cultivated  species 
there  are  unlimited  modifications.  The  crossing  of  one  species 
with  another  species  gives  rise  to  a  hybrid. 

Regarding  the  point  of  nomenclature  and  limitation  of  principle 
of  priority,  it  was  agreed  at  the  congress  that  botanical  nomen- 
clature should  begin  with  the  Species  Plantarum  of  Linnaeus, 
ed.  i  (1753),  for  all  groups  of  vascular  plants.  It  was  further 
agreed  to  associate  genera,  the  names  of  which  appear  in  this 
work,  with  descriptions  given  of  them  by  him  in  his  Genera  Plan- 
tarum,  ed.  5  (1754).  However,  to  avoid  disadvantageous  changes 
in  the  nomenclature  of  genera  by  the  strict  application  of  the  rules 
of  nomenclature,  and  especially  of  the  principle  of  priority  in 
starting  from  1753,  the  rules  provide  a  list  of  names  which  must 
be  retained  in  all  cases.  These  names  are  by  preference  those 
which  have  come  into  general  use  in  the  fifty  years  following  their 
publication,  or  which  have  been  used  in  monographs  and  important 
floristic  works  up  to  the  year  1890. 

Among  the  recommendations,  the  following  suggestions  were 
made  in  regard  to  the  nomenclature  of  divisions,  classes,  families, 
genera,  and  species : 

i.  Names  of  divisions  and  subdivisions,  of  classes  and  sub- 
classes are  taken  from  one  of  their  characters.  They  are  expressed 
by  words  of  Greek  or  Latin  origin,  some  similarity  of  form  and 
termination  being  given  to  those  that  designate  groups  of  the  same 
nature,  as  Angiospermae,  Gymnospermae ;  Monocotyledoneae,  Di- 
cotyledonese ;  Coni ferae;  Pteridophyta.  Among  Cryptogams  old 


BOTANICAL  NOMENCLATURE.  433 

family  names  such  as  Fungi,  Lichenes,  Algae,  may  be  used  for 
names  of  groups  above  the  rank  of  family. 

2.  Orders  are  designated  preferably  by  the  name  of  one  of  their 
principal  families,  with  the  ending  -ales,  e.g.,  Polygonales  from 
Polygonaceae.     Suborders  are   designated   in   a   similar  manner, 
with  the  ending  -ineae,  e.g.,  Malvineae  from  Malvaceae.    But  other 
terminations  may  be  retained  for  these  names,  provided  that  they 
do  not  lead  to  confusion  or  error. 

3.  The  names  of  families  are  designated  by  the  name  of  one  of 
their  genera  or  ancient  generic  names  with  the  ending  -aceae,  e.g., 
Rosacese  from  Rosa,  etc.     The  following  names,  owing  to  long 
usage,  are  an  exception  to  the  rule :  Palmae,  Gramineae,  Cruciferae, 
Leguminosae,  Gutti ferae,  Umbelli ferae,  Labiatae,  and  Compositae. 

4.  The  names  of  genera  should  be  substantives  (or  adjectives 
used  as  substantives)  in  the  singular  number  and  written  with  a 
capital  letter,  which  may  be  compared  with  our  own  family  names. 
These  names  may  be  taken  from  any  source  whatever  and  may 
even  be  composed  in  an  absolutely  arbitrary  manner,  as  Rosa, 
Convolvulus,  Liquidambar,  Impatiens,  and  Manihot. 

5.  The  names  of  all  species,  even  those  that  singly  constitute 
a  genus,  are  designated  by  the  name  of  the  genus  to  which  they  be- 
long, followed  by  a  name  (or  epithet)  termed  specific,  usually  of 
the  nature  of  an  adjective  (forming  a  combination  of  two  names,  a 
binomial,  or  binary  name).    The  specific  name  should,  in  general, 
give  so-me  indication  of  the  appearance,  the  characters,  the  origin, 
the  history,  or  the  properties  of  the  species.     If  taken  from  the 
name  of  a  person,  it  usually  recalls  the  name  of  the  one  who  discov- 
ered o-r  described  it,  or  was  in  some  way  concerned  with  it.  Specific 
names  begin  with  a  small  letter,  except  those  which  are  taken  from 
names  of  persons  or  those  which  are  taken  from  generic  names. 

The  student  should  endeavor  to  fix  in  mind  the  general  prin- 
ciples concerning  botanical  nomenclature  and  should  devote  special 
attention  to  the  generic  and  specific  names  and  the  rules  which 
govern  their  formation.  In  addition  he  should  familiarize  himself 
with  the  meaning  of  the  names,  as  this  will  enable  him  to  memorize 
and  spell  them  correctly.  The  following  is  a  partial  list  of  some  of 
the  principal  generic  and  specific  names,  giving  as  far  as  possible 
the  origin  of  the  names  and  their  significance: 
28 


434  A  TEXT-BOOK  OF  BOTANY. 

Abelmoschus.     Muskmallow.     From  Arab.  Abu-l-misk,   father  of  musk; 

producing  musk. 

Abies.     Fir.     The  classical  Latin  name. 
Abrotanum.     Southernwood.     Gr.    afipdrovov ',   from    aflpoToc ?  sacred  to  the 

gods,   immortal ;   probably  in  allusion  to  the  odor. 
Abrus.     Indian   licorice.     From   Gr.    a/fydf,    graceful;    in   allusion  to   the 

flowers. 

Absinthium.     Wormwood.     The  ancient  Greek  name. 
Abyssinicus-a-um.     Pertaining  to  Abyssinia. 
Acacia.     The  ancient  Greek  name  of  an  Egyptian  species.     From  a*i?,  a 

point ;  referring  to  the  thorns. 
Acer.     Maple.     The  classical  Latin  name. 
Acer,  acris,  acre.     Sharp,  pungent.    From  root  ak,  to  be  sharp. 
Achillea.     Yarrow,  Milfoil.     Named  for  the  Greek  warrior  Achilles,  who 

is  said  to  have  discovered  the  virtues  of  the  plant. 
Aconitum.     Monkshood,  Wolfsbane.    The  ancient  Greek  name. 
Acorus.     Sweet  flag.     The  ancient  classical  name. 
Actaea.    Baneberry,  Cohosh.    Ancient  Greek  name  of  the  elder. 
Acuminatus-a-um.     Acuminate,  tapering.     Lat.  acumino,  to  make  pointed. 
Acutifolius-a-um.     Having   sharp-pointed   leaves.     Lat.   acutus,   sharp,  -f- 

folium,  a  leaf. 
Adiantum.     Maidenhair.    The  ancient  name.    From  Gr.  «,  priv.,  +  diaivu,  to 

wet,  hence  unwetted,  incapable  of  being  wet. 
Adonis.     Pheasant's  eye.     A  plant  fabled  to  have  sprung  from  the  blood 

of  the  beautiful  Adonis. 
Advena.     Yellow  pond  lily.     From  Lat.  advena,   strange,   foreign.      (Of 

doubtful  application.) 
Aegle.     Bengal  quince.     Name  of  a  nymph  in  Greek  mythology.     Perhaps 

from  aty/b?,  brightness,  splendor. 

^sculus.    Horsechestnut.    The  Latin  name  of  an  oak  or  some  other  mast- 
bearing  tree. 
y£stivalis-e.      Pertaining  to   the   summer.     The   classical   Latin   word   is 

(ustivalis. 

Agaricus.     Mushrooms.     Gr.   ayapmov.     Lat.  agarici(m,  a  tree  fungus. 
Agave.      American   aloe.      Gr.     dyaw?,    noble,    illustrious.      Appropriately 

applied  to  Agave  americana,  the  century  plant. 
Agrimonia.     Probably  a  corruption  from  argemone.    According  to  others, 

it  is  derived  from  Gr.  dypdf,  field,  +  JJLOVO^^  alone. 
Agropyron.    Wheat  grass.     From  Gr.  dypdr,  field,  +  nvpos,  wheat ;  alluding 

to  the  fact  that  it  grows  wild  in  wheat  fields. 

Agrostemma.     Corn  cockle.     From  Gr.  dypdf,  field,  +  <n-f////a,  a  crown. 
Ailanthus.     Tree  of  heaven.      Said  to  be  from  aylanto,  the  name  of  the 

tree  in  the  Moluccas,  in  allusion  to  its  height. 
Ajuga.       Bugle  weed.       From  Gr.  a  priv.,  +  (.vyov   (Lat.  iugum),  a  yoke. 

From  the  fact  that  the  lower  lip  of  the  corolla  has  a  single,  con- 
spicuous   middle    lobe. 


BOTANICAL  NOMENCLATURE.  435 

Albizzia.  Name  derived  from  the  Albizzi,  a  noble  family  of  Italy,  one 
of  whom  is  said  to  have  introduced  this  genus  into  European  culti- 
vation. 

Albus-a-um.     White. 

Alchemilla.  Lady's  mantle.  From  the  Arabic  name  alkemelyeh;  in  refer- 
ence to  the  silky  pubescence  of  some  species. 

Aletris.  Star  grass,  Colic-root.  From  Gr.  dAer/Mf,  a  female  slave  who 
grinds ;  in  allusion  to  the  mealy  appearance  of  the  blossoms. 

Algae.  Plural  of  alga,  sea-weed ;  probably  a  shortened  form  of  alliga,  from 
ad,  to,  +  ligo,  to  bind. 

Allium.  Onion,  Garlic.  The  ancient  Latin  name  for  garlic;  perhaps  con- 
nected with  Lat.  oleo,  to  emit  a  smell. 

Alnus.     Alder.     The  ancient  Latin  name. 

Aloe.    The  ancient  Greek  name. 

Alsine.     Chickweed.     Greek  name   of  a  plant. 

Alstonia.  Dita.  Named  for  Dr.  Charles  Alston,  botanist,  of  Edinburgh 
(1683-1/60). 

Althaea.  Marshmallow.  Hollyhock.  The  classical  name.  From  Gr. 
aMaivu,  to  heal,  cure ;  in  allusion  to  the  medicinal  properties  of  the 
plant. 

Alyssum.  Greek  name  of  a  plant  believed  to  check  hydrophobia ;  from  a 
priv.,  +  ^vooa,  raging  madness.  Or  a  plant  used  to  check  hiccup ; 
from  a  priv.,  +  Mfa,  to  have  the  hiccup. 

Amaranthus.  Amaranth.  From  Gr.d^apairof,  unfading;  because  the  bracts 
are  dry  and  persistent. 

Amarus-a-um.     Bitter. 

Amaryllis.     Belladonna  lily.     Greek  name  of  a  shepherdess. 

Ambrosia.  Ragweed.  The  Greek  and  Latin  name  of  several  plants,  as 
well  as  of  the  food  of  the  immortals. 

Ambrosioides.     Gr.  a/ufipoaia  -f-  o-  eitif/G,  like,  resembling  ambrosia. 

Americanus-a-um.     Belonging  to  America. 

Ammania.  Named  for  Paul  Ammann,  a  German  botanist  prior  to 
Linnaeus. 

Ammoniacum.  A  resinous  gum  which  exudes  from  a  tree  that  grew  near 
the  temple  of  Jupiter  Ammon.  The  Greek  name. 

Amomum.     Cardamom.     Greek  name  of  an  Indian  spice  plant. 

Amorpha.  False  indigo.  From  Gr.  d/zopc&of,  deformed,  a,  priv.,  +  /«y)0#, 
form ;  in  allusion  to  the  absence  of  four  of  the  petals. 

Amygdalus.  Almond.  Peach.  Ancient  Greek  name.  From  a^va™,  to 
tear,  rend ;  in  allusion  to  the  furrows  on  the  endocarp. 

Amylum.  Starch.  The  Greek  name.  From  a  priv.,  +  /^Xr;,  a  mill ;  re- 
ferring to  its  fineness,  which  makes  it  unnecessary  for  it  to  be  ground. 

Anacardium.  Cashew.  From  Gr.  avd,  similar  to,  +  Kapdia,  heart.  The 
fruit  of  the  plant  is  thought  to  resemble  the  heart  of  a  bird. 

Anacyclus.  Pellitory.  An  abbreviation  for  ananthocyclus.  From  Gr.  a 
priv.,  -j-  a/^of,  flower,  -f-  KVK^OC,  circle ;  in  allusion  to  the  pistillate 
or  infertile  rays.  Meaning  rather  vague. 


43*6  A  TEXT-BOOK  OF  BOTANY. 

Anagallis.     Pimpernel.     The  ancient   Greek  name.     Probably   from   dvd} 

again,  -f  Ayd\\ut  to  delight  in. 

Anamirta.     An  Indian  name  synonymous  with  Menispermum. 
Ananas.     Pineapple.    Sp.  ananas,  from  the  native  American  name. 
Andira.    Vouacapoua.     From  the  vernacular  Brazilian  name. 
Andropogon.    Beard  grass.    From  avfip,  avdp6s,  man,  +  TTW/WV,  beard. 
Anemone.    Wind  flower.    The  ancient  Greek  name.    From  dve//oc,  wind. 
Anethum.     Dill.     The  ancient  Greek  name.     Probably  related  to  aviaov, 

anise. 
Angelica.     From  Gr.   dyye/lof ,  messenger,  angel ;  in  allusion  to  its  cordial 

and  medicinal  properties. 

Angostura.    Name  of  a  city  in  Venezuela,  whence  angustura  bark  is  im- 
ported. 
Angustifolius-a-um.    Having  narrow  leaves.    From  Lat.  angustus,  narrow, 

+  folium,  leaf. 

Anisum.     Anise.     Gr.  avioov,  avrjdov, 

Annuus-a-um.     Of  one  year's  duration.    Lat.  annus,  a  year. 
Anogra.     Evening  primrose.     Name    formed   by   transposition   of   letters 

of  Onagra,  another  name  for  this  plant. 
Anthelminticus-a-um.       Worm-destroying.       From     Gr.    avTt)     against,  -f- 

etyivs,  worm. 

Anthemis.    The  ancient  Greek  name  of  chamomile. 
Anthoxanthum.     Sweet  vernal  grass.     From   Gr.  avQos,  flower,  -f-  t-avOoq^ 

yellow. 

Aparine.     Cleaverwort.     The  ancient  Greek  name  of  a  plant. 
Apocynum.     Dogbane.     Indian  Hemp.     The  classical  name.     From  cnr6f 

from,  +  KVUV,  dog. 

Aquaticus-a-um.    Growing  in  or  by  the  water. 
Aquifolium.     Holly-leaved  barberry.     Ancient  Latin  name   for  the  holly 

tree  or  the  scarlet  holm. 
Arabicus-a-um.    Pertaining  to  Arabia. 
Aralia.     Derivation  of  name  unknown. 

Araroba.     From  East  Indian  name  ar(ar)oba  as  applied  to  the  bark. 
Arctium.    Burdock.    From  Gr.  d^/crof,  a.  bear,  or  apKrtov,  a  plant. 
Arctostaphylos.     Bearberry.     From  Gr.  d/o/crof ,  a  bear,  -j-  ara^vA?/,  a  bunch 

of  grapes. 

Areca.    Betel-nut.    Sp.  and  Port,  areca,  from  East  Indian  vernacular  name. 
Argemone.     Prickly  poppy.    The  ancient  Greek  name  for  poppy.     Accord- 
ing to  others,  from    apye/ua,    a  disease  of  the  eye,  for  which  the  juice 

of  a  plant  so  called  by  the  Greeks  was  a  supposed  remedy. 
Argithamnia.    From  Gr.    apyvpoe,  silver,  +  dd/uvo?,  bush ;  from  the  hoari- 

ness  of  the  original  species. 
Arissema.     Indian  turnip.     From  Gr.  dp^,  a  kind  of  arum,  -f-  al/ta,  blood ; 

from  the  spotted  leaves  of  some  species. 
Aristolochia.     Birthwort.     From   Gr.  apiaro?,   best,  +   Ao^e/a,    child-birth; 

once  thought  to  ease  labor. 


BOTANICAL  NOMENCLATURE.  437 

Arnica.     From  Gr.     dpva/c/?,     sheepskin,  Lat.  arnacis,  a  coat  of  sheepskin; 

in  reference  to  the  hairy  stem  and  leaves  ;  or,  according  to  others, 

from  Gi'.   irrapp.tK.6^^   Lat.  ptarmicus,  causing  to  sneeze. 
Aromaticus-a-um.     Aromatic,  fragrant. 
Artemisia.    Wormwood,  ancient  Greek  name  of  an  herb.    From  the  queen 

Artemisia,  wife  of  Mausolus. 

Artemisiasfolius-a-um.    Having  leaves  resembling  those  of  Artemisia. 
Artocarpus.     Breadfruit.     From  Gr.  <$prof,  bread,  +  /CO/OTTO^,  fruit. 
Arum.     Also  Aron.     The  ancient  Greek  name  apov. 
Arundinaceus-a-um.    Reed-like.    From  Lat.  arundo,  a  reed. 
Arvensis-e.    Cultivated.    From  Lat.  arva,  an  arable  field. 
Asagraea.     From  Asa  Gray,  the  eminent  American  botanist. 
Asarum.     Hazelwort,  Wild  ginger.     The  ancient  Greek  name. 
Asclepias.    Milkweed,  Silkweed.    Named  in  honor  of  ^sculapius,  the  Latin 

tutelary  god  of  medicine. 
Asimina.    North  American  papaw.    The  Northern  Algonkin  corruption  of 

rassimina,  in  allusion  to  the  shape  of  the  fruit. 
Asparagus.     From  the  ancient  Greek  name    aairapayos,  asparagus. 
Asperula.     Woodruff  weed.     From  Lat.  asper,  rough  ;  in  allusion  to  some 

scabrous  species. 
Aspidium.    Shield  fern.    From  Gr.    dc-rruhov,    a  little  shield  ;  from  the  shape 

of  the  indusium. 
Aspidosperma.    From  Gr.  a<T7r/c,    a  shield,  +  atrlp/na,  seed  ;  from  the  shape 

of  the  seed. 
Asplenium.    Spleenwort.    From  Gr.  a  priv.,  +  ffTrAr/u,    the  spleen  ;  because 

of  its  supposed  remedial  properties. 

Astragalus.     Milk  vetch.     Gr.  acrrpdyaAof,   a  leguminous  plant. 
Athamanticus-a-um.    Of  Athamas,  a  mountain  in  Thessaly  ;  with  reference 

to  the  habitat  of  the  plant. 
Atriplex.     The  ancient  Latin  name  for  orach;  a  corruption  of  the  Greek 


Atropa.     Name  from  "ArpoTrof,  one  of  the  Greek  Fates  ;  from  a  priv.,  + 

rpoTn?,  a  turn  ;  hence  unchangeable,  inflexible. 
Atropurpureus-a-um.     From   Lat.  ater,   dark,  -f-  purpureus,   purple  ;    dark 

purple. 
Aurantium.    Orange.    From  Lat.  aurum,  gold,  referring  to  the  color  of  the 

fruit. 

Australis-e.     Southern.     Lat.  auster,  the  South  wind. 
Autumnalis-e.    In  the  autumn  ;  referring  to  the  time  of  blooming. 
Avena.     Oats.     The  classical  Latin  name. 
Baccharis.     Groundsel  tree.     The  classical  name  of  a  shrub  dedicated  to 

Bacchus. 

Baccifer-a-um.    Producing  berries.    Lat.  bacca,  a  berry,  +  fero,  to  bear. 
Ballota.    Fetid  horehound.    The  ancient  Greek  name. 


438  A  TEXT-BOOK  OF  BOTANY. 

Balsamifer-a-um.     Producing  balsam.     Lat.  balsamum,  balsam,  +  fero,  to 

bear. 
Balsamum-ea.    The  classical  name  of  the  several  trees  yielding  a  balsam; 

also  in  allusion  to  the  balsamic  oleo-resins  obtained  from  the  trees. 
Baptisia.     False  indigo.     From  Gr.  /3a7rr/£w,   to  dye. 
Barbarea.    Winter  cress.    Anciently  called  the  Herb  of  St.  Barbara. 
Barosma.    Buchu.     From  Gr.  {3api>ef  heavy,  +  6o/«#,   odor ;  in  reference  to 

its  strong  smell. 
Belladonna.     Ital.  bella,  beautiful,  -j-  donna,  lady.     It  is  said  that  Italian 

ladies  used  the  berries  as  a  cosmetic  and  to  dilate  the  pupil  of  the 

eye,  thus  giving  themselves  a  striking  appearance. 
Benedictus-a-um.     Blessed,  consecrated.     Past  participle  of  Lat.  benedico, 

to  bless. 

Benzoin.    Wild  allspice,  Fever  bush.     Named  from  its  odor,  which  resem- 
bles that  of  benzoinum. 
Benzoinum.    A  resinous  substance  from  Styrax  Benzoin,  a  tree  of  Sumatra, 

Java.     French  benjoin,  from  Arabic  luban-jawi,  incense  of  Java. 
Berberis.     Barberry.     Name  derived  from  berberys,  the  Arabic  name  of 

the   fruit. 

Beta.    Beet.    The  ancient  Latin  name. 
Betonica.    Betony.    The  ancient  Latin  name  (betonica,  vcttonica)  of  wood 

betony. 

Betula.    Birch.    The  ancient  Latin  name. 
Betulinus-a-um.     Pertaining  to  birch ;  alluding  to  the  fact  that  the  leaves 

resemble  birch  leaves. 

Bidens.    Bur  marigold.    From  Lat.  bidens,  two-toothed. 
Biennis-e.    Of  two  years'  duration.    Lat.  bis,  twice,  +  annus,  year. 
Biflorus-a-um.    Bearing  two  flowers,  biflorate. 
Bignonia.    Named  for  the  Abbe  Jean 'Paul  Bignon,  court-librarian  at  Paris 

and  friend  of  Tournefort. 
Bistorta.    Adderswort.    From  bis,  twice,  +  tortus  (past  participle  of  tor- 

queo),  twisted. 
Boehmeria.     False  nettle.    Named  after  G.  R.  Boehmer,  German  botanist 

and  professor  at  Wittenberg  in  the  eighteenth  century. 
Botrychium.    Moonwort.    From  Gr.  /3<5r/ouf,    a  bunch  of  grapes;  from  the 

appearance  of  the  fructification. 
Brachycerus-a-um.     Having   short   horns.     From   Gr.    /3pa^,    short,   -f- 

/cfpaf,  a  horn. 

Brasiliensis-e.     Belonging  to  Brazil. 

Brassica.     Mustard.    Turnip.     The  ancient  Latin  name  for  cabbage. 
Brauneria.      Purple    cone-flower.      Named    for   Jacob    Brauner,    German 

botanist  of  the  eighteenth  century. 
Bryonia.    Bryony.    The  ancient  Greek  name.    From  ppvu,    to  swell,  grow 

luxuriantly. 
Bursa.    Capsella.    Bursa  is  a  late  Latin  word  meaning  purse. 


BOTANICAL  NOMENCLATURE.  439 

Bursa-pastoris.     Shepherd's  purse. 

Butneria.     Spice  bush. 

Buxus.    Boxwood.    The  ancient  Latin  name.    Gr.  TTI>£O?. 

Cacao.     Span,  from  Mex.  kakahuatl;  native  name  of  the  tree  Theobroma 

Cacao. 

Cactus.    The  ancient  Greek  name  of  some  thorny  plant. 
Caesalpinia.     Sappan.     Named  for  Andreas   Csesalpinus,  Italian  botanist, 

who  died  in  1603. 
Cajuputi.    Name  of  Malayan  origin.     From  kayu,  tree,  -j-  putih,  white;  in 

reference  to  the  appearance  of  the  branches. 
Calamus.    Reed,  cane.    The  classical  word.    So  named  because  its  scape  is 

reed-like. 
Calendula.     Marigold.    Lat.  calendar,  calends,  the  first  day  of  the  month ; 

so  called  because  it  flowers  every  month. 
Californicus-a-um.  Pertaining  to  California. 
Calisaya.  A  name  given  to  the  bark  of  a  tree  of  Peru  by  Spaniards  and 

Indians. 
Calla.     Water  arum.     Linnaeus  derived  calla  from  Gr.   /cdAAam,  a    cock's 

wattles,  but  compare  Lat.  calla,  calsa,  name  of  an  unknown  plant,  and 

Greek  /caAdf,    beautiful. 
Calluna.    Heather.     From  Gr.   /caAluvw,    to  brush  or  sweep,  brooms  being 

made  from  the  twigs. 

Calophyllum.    Tacamahac.    From  Gr.  AcaAdf,  beautiful,  +  <f>vMov,   a  leaf. 
Caltha.    Marsh  marigold.    An  ancient  Latin  name  for  the  common  mari- 
gold. 

Calumba.     From  kalumb,  its  native  name  in  Mozambique. 
Cambogia.    From  Cambodia,  a  French  protectorate  in  Farther  India. 
Camelina.    False  flax.     From  Gr.  xaC-a'1,   dwarf,  -}-  Xfvov,   flax. 
Campechianus-a-um.     Belonging  to  Campeachy. 
Campestris-e.     Growing  in  uncultivated  fields. 
Camphora.    Gr.   KaQovpd,  from  Arab,  kafur,  camphor. 
Camptosorus.    Walking  leaf.     From  Gr.   Aca/jTrrdf,    flexible,  -f-  oup6$t   sorus, 

fruit  dot. 

Canadensis-e.    Of  or  belonging  to  Canada. 
Cannabinus-a-um.     Pertaining  to  cannabis. 
Cannabis.    Hemp.    The  ancient  Greek  name. 
Caoutchouc.     Native  South  American  name  for  the  milky  sap  of  several 

plants.    Also  called  India  rubber. 

Capillaceus-a-um.    Hairy,  very  slender,  like  a  hair.    From  Lat.  capillus,  hair. 
Capillus-Veneris.    Maidenhair.    The  Latin  for  hair  of  Venus. 
Capsella.     Shepherd's  purse.    Diminutive  of  capsa,  a  box. 
Capsicum.    Red  pepper.    From  Lat.  capsa,  a  box ;  alluding  to  the  shape  of 

the  fruit.    Or  from  Gr.  /mTrrw,   to  bite,  from  its  hot,  pungent  properties. 
Cardamomum.    The  ancient  classical  name  for  the  spice  cardamom. 
Carex.    Sedge.    The  ancient  Latin  name. 


440  A  TEXT-BOOK  OF  BOTANY. 

Carica.    Papaw.    The  Latin  name  for  dried  fig,  from  Caria,  in  Asia  Minor. 

Carolinensis-e.  i 

Carolinianus-a-um.  }  Bel^ing  to  Carolina. 

Carota.     Carrot.    The  classical  Latin  word. 

Carpinus.    Hornbeam.    The  ancient  Latin  name. 

Carum.    Caraway.    Gr.  xdpov,  Lat.  careum.    Probably  from  Caria,  in  Asia 

Minor.  • 

Carvi  or  Carui.    Probably  an  assimilated  Latin  genitive,  as  in  Carui  semina. 
Caryophyllus.    Cloves.    From  Gr.   napvov,    nut,  +  0{vUov,  a  leaf ;  referring 

to  the  appearance  of  the  flower  buds. 

Cascara  Sagrada.     Span.  Cascara,  bark,  and  sagrada,  sacred ;  holy  bark. 
Cascarilla.    The  bark  of  a  Peruvian  tree.    Diminutive  of  cascara. 
Cassia.     Senna.     An  ancient  Greek  plant  name  Kaaia,    probably  from  the 

Hebrew  getsiah,  gatsa,  to  cut,  peel  off. 
Castanea.    The  chestnut  tree.     The  ancient  Latin  name,  from  a  town  in 

Thessaly. 

Catalpa.    Indian  bean.    The  aboriginal  name. 
Cataria.    Catnip.    From  late  Latin  catus,  a  cat. 
Catechu.    East  Indian  name  of  extract  from  the  acacia  tree,  applied  natively 

to  all  astringent  extracts. 
Cathartocarpus.     Cleansing,   purgative.     From   Gr.  KaQaprLKog,  cleansing,  _|_ 

Kapn6c,  fruit. 
Caulophyllum.    Blue  cohosh.    From  Gr.    /rau/ldf,  a  stem,  +   ^i/A/tov,  a  leaf ; 

a  stem-leaf. 

Ceanothus.     Red  root.     Gr.  KedvuOo?,  a  kind  of  thistle. 
Cedron.     Cedron  seed.    From  Gr.   Ketipov,  the  fruit  of  the  cedar. 
Celastrus.    Staff  tree.    The  ancient  Greek  name  of  an  evergreen  tree. 
Centaurea.     Star  thistle.     Ancient  Greek  name  of  a  plant.     The  plant  of 

the  Centaurs. 
Centifolius-a-um.    Having  a  hundred  leaves  or  petals.    From  Lat.  centum, 

hundred,  +  folium,  a  leaf. 
Cephaelis.     Ipecacuanha.     From  Gr.    Ke0a/t#,  head,  +  eUw,    to  collect,  roll 

up.    The  flowers  are  collected  into  a  capitulum. 
Cephalanthus.      Buttonbush.      From    Gr.     KetyaAJ],    head,  -f-    av6o?t     flower. 

Flowers  aggregated  in  spherical  peduncled  heads. 
Ceratonia.     St.  John's  bread.     Greek  name  for  the  carrob  or  locust  tree. 

From  K.ipaq ,    a  horn ;  alluding  to  the  horn-shaped  pods. 
Cerealis-e.     Pertaining  to  grain  or  agriculture.     From   Ceres,  the  Latin 

goddess  of  agriculture. 
Cetraria.     Iceland  moss.     From  Lat.  ccetra,  a  shield ;  in  reference  to  the 

shield-shaped  apothecia. 
Chamaenerion.     Willow-herb.     From  Gr.  ^a^at,  on  the  ground,  -f-  vypiov, 

rose-laurel. 
Chamomilla.     Earth  apple.     From  Gr.    xaftai,   on  tne  earth,  +  ^ov,   an 

apple.     From  the  apple-like  odor  of  the  flowers. 


BOTANICAL  NOMENCLATURE.  441 

Chekan.    The  Chilian  name  of  Eugenia  Chekan. 

Chelidonium.     Celandine.      From    Gr.    ^efoduv,     a   swallow,    the    flowers 

appearing  at  the  same  time  as  the  swallows. 
Chelone.     Turtlehead.     Snakehead.     From   Gr.    x£^vrf,     a   tortoise,   the 

corolla  being  shaped  like  the  head  of  a  reptile. 
Chenopodium.     Goosefoot.     Pigweed.     The  ancient  Greek  name.     From 

XTJV,    goose,  +  Trovf,    foot. 
Chimaphila.     Pipsissewa.    Bitter  wintergreen.    Love-in-winter.    From  Gr. 

Xeifta,  winter,  +  ^^«,  to  love ;  in  allusion  to  the  several  popular  names. 
Chionanthus.  Fringe-tree.  From  Gr.  ^6v,  snow,  +  av6ofj  flower ;  in  refer- 
ence to  the  snow-white  clusters  of  the  flowers. 
Chirata  or  Chirayita.    From  the  Hindoo  name  chiraita. 
Chondrodendron.     From  Gr.    ^6v6pogf  <a  granule  +  6ev6pov,    a  tree ;  allud- 
ing to  the  warty  protuberances  on  the  bark. 
Chondrus.     Sea  moss.     From  Gr.    xovdpoc,    cartilage ;  in  reference  to  the 

cartilaginous  fronds. 

Chrysanthemum.    Gold-flower.    The  ancient  Greek  name. 
Chrysarobinum.     From  Gr.   xPva6a,  gold,  -f-  araroba,  a  foreign  name  of 

Goa  powder. 

Chrysophyllum.    Star  apple.    From  Gr.    ^pwrrff,    gold,  +  0t>2/W,   leaf. 
Chrysosplenium.     Golden  saxifrage.    From  Gr.  xpvats,  gold,  +   trrr^i;,   the 

spleen.    From  its  reputed  medicinal  properties. 
Cichorium.     Gr.   /a'^opa,  'Succory,  Chicory. 

Cicuta.    Water  hemlock.    The  ancient  Latin  name  of  the  hemlock. 
Cimicifuga.     Bugbane.     From  Lat.  civnex,  a  bug,  -f-  fugo,  to  drive  away. 
Cinchona.    Named  for  the  countess  of  Chinchon,  who  brought  the  remedy 

to  Europe,  when  she  returned  with  her  husband,  viceroy  of  Peru,  in 

1640. 

Cinereus-a-um.    Ash-colored.    From  Lat.  cinis,  ashes. 
Cinnamomum.     Cinnamon.     The  classical  name. 

Circaea.    Enchanter's  nightshade.    Named  after  the  enchantress  Circe. 
Cissampelos.     From  Gr.   Ktaaoc;,    ivy,  +    a/nre/lof,   vine.     From  the  fact  that 

it  climbs  like  the  ivy. 

Citrullus.    Melon.    From  Lat.  citrus,  the  citron  tree. 
Citrus.     Citron,  Orange.    The  Latin  name  for  the  citron  tree. 
Clava-Herculis.     Club  of  Hercules;  from  the  appearance  of  the  cone-like 

cork-wings. 

Clavatus-a-um.     Club-like.    From  clava,  a  club. 
Claviceps.     Ergot.     From  Lat.  clava,  a  club,  +  caput,  head ;  alluding  to 

the  shape  of  the  mycelium  or  sclerotium. 
Clematis.     Virgin's  bower.     Greek  name  of  a  creeping  plant  with  long, 

lithe  branches.     Probably  clematis  or  periwinkle. 
Clinopodium.     Field  thyme.     Calamint.     From  Gr.    KMvq,    a  -bed,  +  Trod?, 

foot. 
Clove.    From  Lat.  clavus,  a  nail ;  in  allusion  to  the  shape  of  the  dried  fruit. 


442  A  TEXT-BOOK  OF  BOTANY. 

Cnicus.    Blessed  thistle.    Latin  name  of  the  safflower,  from  the  Gr. 

Coca.    Span,  from  native  name  of  tree. 

Cocculus.     Diminutive  of  coccus,  a  berry. 

Cochlearia.    Scurvy  grass.     From  Gr.    Koxfadptov,    a  spoon ;  with  reference 

to  the  shape  of  the  leaves. 

Coffea.     Coffee.     From  Turk,  qahveh,  Arab,  qahuah,  name  of  a  beverage. 
Colchicum.    Meadow  saffron.    From  Gr.  Ko^xk ,  Colchis,  an  ancient  province 

in  Asia  Minor,  where  this  plant  flourished. 
Collinsonia.     Horsebalm.     Named   in   honor  of   Peter   Collinson,   English 

botanist  of  the  eighteenth  century. 

Colocynthis.     From  Gr.   KofoitvvOq,    a  gourd  or  pumpkin. 
Commelina.     Day-flower.      Named   after   the   Dutch   botanists   J.    and    G. 

Commelin,  who  lived  in  the  seventeenth  century. 
Commiphora.    Myrrh.    From  Gr.  KO////<,  gum,  -f-  Qopoc,   bearing ;  in  allusion 

to  the  exudation. 
Communis-e.     Common,  general. 

Conifer-a-um.     From  Lat.  conns,  a  cone,  -f  fero,  to  bear,  cone-bearing. 
Conium.     Poison  hemlock.     From  KUVCIOV,  the  Greek  word  for  hemlock. 
Convallaria.    Lily  of  the  valley.     From  Lat.  convallis,  a  valley. 
Convolvulus.      Bindweed.      The    ancient    Latin    name    from    convolve,    to 

entwine. 
Copaiba.     Span,  and  Port,  from  Brazil,  cupauba,  the  native  name  of  the 

tree  and  its  product. 
Coptis.     Goldthread.     From  Gr.  KOTTTU,  to  cut;  in  allusion  to  the  divided 

leaves. 

Corallorhiza.     Coral  root.     From  Gr.    KopdMtov,  coral,  +  j>%a,  root. 
Cordifolius-a-um.     Heart-leafed.     From  Lat.  cor,  cordis,  heart,  +  folium, 

leaf. 

Coriandrum.     Coriander.    The  ancient  Latin  name,  from  Gr.  Kopiavvov. 
Coriarious-a-um.     Pertaining  to  leather.    Lat.  corium,  leather. 
Cornus.     Cornel.     Dogwood.     From  Lat.  cornu,  a  horn;  alluding  to  the 

hardness  of  the  wood. 
Coronilla.    Axseed.    Diminutive  of  Lat.  corona,  a  crown;  alluding  to  the 

inflorescence. 
Corylus.    Hazelnut,  Filbert.    The  classical  name.    Probably  from  Gr.    Kopvf, 

a  helmet,  from  the  helmet-like  involucre. 
Cotula.     Mayweed.     From  Gr.  nonfat,   a  hollow. 
Cratsegus.     Hawthorn.     The  Greek  name  of  a  kind  of   flowering  thorn. 

Perhaps  derived  from  /cpdro?,   strength. 

Crenulatus-a-um.     Notched.     From  crena,  a  notch,  referring  to  the  leaves. 
Crispus-a-um.     Curled,  crisped. 
Crocus.     Saffron.     The  ancient  Greek  name.     According  to  mythology,  a 

youth,  Crocus,  was  changed  into  this  flower. 
Crotalaria.    Rattle-box.    From  Gr.  Kp6rafant,  a  rattle ;  from  the  rattling  of 

the  loose  seeds  in  the  pod. 


BOTANICAL  NOMENCLATURE.  443 

Croton.     From  Gr.  uporuv  or  Kpdruv,  a  tick,  because  the  seed  was  thought 

to  resemble  a  tick.     Also  applied  to  the  castor-oil  seed. 
Crucifer-a-um.     Cross-bearing.     From   Lat.   crux,  cross,  -\-fcro,  to  bear. 

With  reference  to  the  form  of  the  flowers. 

Cruciger-a-um.     Cross-bearing.     From   Lat.   crux,  cross,  +  gero,  to  bear. 
Cubeba.    Span,  and  Port,  from  Arab,  kababat,  native  name  of  the  plant. 
Cucumis.     Cucumber  Melon.     The  ancient  Latin  name. 
Cucurbita.     Gourd,  Squash.     The  ancient  Latin  name. 
Cuminum.    Cumin.    The  ancient  Greek  name. 

Cunila.     Dittany.    Ancient  Latin  name  for  a  plant,  a  species  of  orizanum. 
Cupana.     After  Father  Francis  Cupani,  Italian  monk  and  botanist ;  died 

in  1710. 

Cusparia.    Angostura. 

Cusso.     Abyssinian  name  of  the  tree  Hagenia  Abyssinica. 
Cyanus.    Blue-bottle.    The  old  Greek  word  for  any  dark-blue  substance. 
Cyminum.     Cumin.     Same  as  cuminum. 
Cynoglossum.    Hound's  tongue.    The  classical  name.     From  KVUV,  dog,  + 

•yAuoaa,  tongue ;  from  the  shape  and  texture  of  the  leaves. 
Cyperus.    Galingale.     From  Gr.  idnreipof,   a  marsh  plant. 
Cypripedium.    Lady's  slipper.    From  Gr.  Kv-npis,  Venus,  -f-  7mhAov,   sandal. 
Cytisus.     Broom.    An  ancient  classical  name  for  a  shrubby  kind  of  clover, 

perhaps  Medicago  arborea. 
Damascenus-a-um.    Pertaining  to  Damascus. 
Daphne.     Mezereum.     Ancient   Greek   name   of   the  bay-tree;    from  the 

nymph,  whom  Apollo  transformed  into  a  laurel. 
Datura.    Jimson  weed.    Thorn  apple.    Name  derived  from  Sans,  dhattura, 

Arab,  tatura,  tatula,  the  native  name. 
Daucus.    Carrot.    The  ancient  Greek  name. 
Decandrus-a-um.      Having    ten    stamens.      From    Gr.    MM,     ten,  -+-  arfp, 

avfipof,    man. 
Delphinium.      Larkspur.      Ancient    Greek    name,     from      dety/f    (rktytv), 

dolphin,  in  allusion  to  the  shape  of  the  flower. 
Dentatus-a-um.     Dentated,  toothed.     Lat.  dens,  tooth. 
Desmodium.     Tick  Trefoil.     From  Gr.    rfeo/zdf,  a  bond  or  chain;    from  the 

connected  joints  of  the  pods. 

Dianthus,  Pink.     Carnation.     From  Gr.  A/df,  oi  Jupiter,  +    avtfof,    flower. 
Dicentra.     From  Gr.  d/f,  twice  ,  -j-  nevrpov,  a  spur. 
Dictamnus.     Dittany.    The  classical  name.     From  Mt.  Dicte,  in  Crete,  on 

which  the  plant  grew  luxuriantly. 

Didymus-a-um.    Twin,  found  in  pairs.     Gr.  didvpoq,  double. 
Diervilla.    Bush  honeysuckle.    Named  for  Dr.  N.  Dierville,  who  carried  it 

from  Canada  to  Tournefort. 
Digitalis.    Foxglove.    Lat.  digitalis,  of  or  belonging  to  the  finger;  alluding 

to  the  finger-shaped  corollas. 


444  A  TEXT-BOOK  OF  BOTANY. 

Dioicus-a-um.    Unisexual.    The  two  sexes  on  different  plants.     Gr.    di-t  61$, 

twice,  -f  okof,  a  house. 

Dioscorea.    Yam.    Dedicated  to  the  Greek  naturalist,  Dioscorides. 
Diospyros.     Persimmon.     From  Gr.    Ai6^f    of  Jupiter,  -f  irvp6gy  grain. 
Diphyllus-a-um.    Having  two  leaves.    Gr.  di-t  dig,  twice,  -{-  <j>vMov,  a  leaf. 
Dipsacus.     Teasel.     The  classical  name.     Probably  from    diipa,  thirst,  be- 
cause the  united  cup-shaped  bases  of  the  leaves  of  some  species  hold 

water. 

Dirca.     Leatherwood.     Moosewood.     Name  of  uncertain  origin. 
Domesticus-a-um.     Domestic,  common. 
Domingensis-e.    Of  Santo  Domingo. 

Dorema.    Ammoniac  plant.    From  Gr.    duprjfia,    a  gift,  benefit. 
Dorstenia.     Contrayerva.     Named  for  T.  Dorsten,  German  botanist,  six- 
teenth century. 
Drosera.     Sundew.    From  Gr.    6poaep6e}    dewy.    The  glands  of  the  leaves 

exude  drops  of  a  clear  glutinous  fluid,  which  glitter  like  dewdrops. 
Dryopteris.     Greek  name  of  a  fern  growing  on  oaks.     From  6pv^t    oak,  + 

Trrepif,  a  fern. 

Dulcamara.    Bittersweet.    From  Lat.  dulds,  sweet,  +  amarus,  bitter. 
Dulcis-e.    Sweet. 
Dysentericus-a-um.     Pertaining  to  dysentery,  dysenteric.     Gr.  6va£VTepin6sy 

afflicted  with  dysentery. 

Ebenaceae.     Ebony  family.     From  Gr.  Ifievoc,  Lat.  ebenus,  ebony. 
Ecballium.    Squirting  cucumber.    From  Gr.  e/c?   out  of,  -f-  /M/l/lw,    to  throw. 
Elasticus-a-um,   Elastic,  gummy.  Probably  formed  from  Gr.&aww,  to  drive. 
Elaterium.     Classic  name  for  a  medicine  prepared  from  the  juice  of  the 

wild  cucumber.    From  Gr.  eTiavvu,  to  drive  away. 
Eleocharis.     Spike  rush.     From  Gr.  £Aof,  a  marsh,  +  ^d/twf,    grace ;  being 

marsh  plants. 

Elettaria.    Cardamom.    From  elettari,  native  name  of  plant  in  Malabar. 
Eleuteria.    From  Eleuthera,  one  of  the  Bahama  Islands. 
Epigaea.     Ground  laurel.     Trailing  arbutus.     From  Gr.    eiri,    upon,  +  yjj, 

earth,  in  reference  to  its  trailing  growth. 
Equisetaceae.     Horsetail   family.     Ancient   Latin   name   equis&tum    (equi- 

seta) ,  the  plant  horsetail. 
Equisetum.    Horsetail.    Ancient  Latin  name.    Derived  from  equus,  horse, 

-f-  s&ta  (seta),  a  bristle. 
Erectus-a-um.    Upright,  elevated,  lofty. 
Ergota.    Ergot.    From  French  ergot,  a  spur. 
Ericaceae.     Heath  family.     From  Gr.  epeiK^9  heath,  heather. 
Erigeron.     Fleabane.      Ancient    Greek    name    of    a    groundsel,    probably 

Senecio  vulgaris.    From  jpit  early,  -f-  -ytpov,  old  man,  from  the  hoary 

appearance  of  some  vernal  species. 
Eriodictyon.     From  Gr.  Ipiov,  wool,  +    diicrvov,   a  net ;  in  allusion  to  the 

woolly,  net-veined  leaves. 


BOTANICAL  NOMENCLATURE.  445 

Erysimum.     Treacle  mustard.   The  Greek  name  of  the  hedge  mustard; 

from   kpvuj   to  draw. 
Erythroxylon.     From  Gr.    ipvdpde,    red,  +   f uA«w,   wood ;   referring  to  the 

color  of  the  trees  or  shrubs. 
Esculentus-a-um.     Good  to  eat,  edible,  esculent. 
Eucalyptus.     From    Gr.   ev}  well,  +   /caAvTrrdf,   covered ;    from   the    conical 

covering  of  the  buds,  which  falls  off  at  anthesis. 
Eugenia.    Clove-tree.    Named  in  honor  of  Prince  Eugene  of  Savoy. 
Euonymus.     Spindle  tree.    Ancient  classical  name  for  a  shrub.     From  Gr. 

et>,  well,  +  dvo/ua,  name. 
Eupatorium.      Thoroughwort.      Dedicated    to    Eupator,    king    of    Pontus, 

who  is  said  to  have  used  one  of  the  species  in  medicine. 
Euphorbia.     Spurge.     Gr.   ev^opjSiov,  name  of  an  African  plant.     Named 

for  Euphorbus,  physician  to  king  Juba. 
Europseus-a-um.    Belonging  to  Europe. 
Excelsus-a-um.     Lofty,  high,  surpassing. 
Exogonium.    From  Gr.  £gwf  outside,  -f-  y6vo$,  offspring;  in  allusion  to  the 

exserted  stamens  and  pistils. 
Fagus.     Beech.     The  ancient  Latin  name,   from  Gr.    yayelv,    to   eat;   in 

allusion  to  the  esculent  nuts.     Compare  ^yof,  a  kind  of  oak  bearing 

esculent  acorn. 
Fagopyrum.     Buckwheat.     From  Lat.  fagus,  beech,  +  Gr.   irvpos,  wheat; 

from  the  resemblance  of  the  grain  to  the  beech-nut. 

Farfara.    Colt's-foot.    Feminine  form  of  farfarus,  the  ancient  Latin  name. 
Farinosus-a-um.     Pertaining  to  meal,  mealy ;  Lat.  farina,  meal. 
Fastigiatus-a-um.     High,  pointed,  tapering ;   with  reference  to  the  shape 

of  the  fruit.    From  Lat.  fastigium,  the  top  of  a  gable,  summit. 
Fertilis-e.    Fruitful,  fertile. 
Ferula.     Asafceticla.    Latin  name  for  the  plant  fennel-giant.     From  ferio, 

to  strike. 

Ficus.    The  ancient  Latin  name  for  fig. 
Filix-mas.     Male  fern.     Lat.  Filix,  fern.    Mas,  male.     In  reference  to  its 

asexual  fructification. 

Fistula.    Reed,  pipe,  cane ;  from  the  appearance  of  the  long,  slender  fruit. 
Fceniculum.     Fennel.     The  classical  Latin  name.     Diminutive  of  fcenum, 

hay. 

Fcetidus-a-um.    Fetid,  stinking.    From  Lat.  factor,  an  offensive  smell. 
Fragaria.     Strawberry.     Lat.  fraga,  strawberries.     From  fragro,  to  emit 

fragrance. 

Fragrans.     Fragrant,  sweet-scented.     Pres.  partic.  of  fragro,  to  emit  fra- 
grance. 
Frangula.     Buckthorn.     From  Lat.  frango,  to  break;   in  allusion  to  the 

brittle  stems. 

Frasera.    American  Calumba.    Named  for  John  Fraser,  an  English  botani- 
cal collector  of  the  eighteenth  century. 


446  A  TEXT-BOOK  OF  BOTANY. 

Fraseri.    Of  Fraser.    Latinized  genitive. 

Fraxinus.  Ash.  The  classical  Latin  name.  Perhaps  from  Gr.  fypdacu,  to 
hedge  in. 

Fulvus-a-um.    Yellow,  tawny. 

Fumaria.  Fumitory.  From  Lat.  fumus,  smoke.  Probably  from  the  nitrous 
odor  of  the  fresh  roots. 

Galeopsis.    Hemp  nettle.    Gr.  yaXioipig,  a  kind  of  dead  nettle. 

Galium.  Bedstraw.  Cleavers.  Ancient  Greek  name  of  a  plant.  Perhaps 
from  yd/la,  milk,  which  is  coagulated  by  some  species. 

Galla.    Nutgall.    Ancient  Latin  word  for  oak-apple,  gall-nut. 

Gallicus-a-um.     Belonging  to  Gaul,  now  France. 

Garcinia.  Mangosteen.  Named  for  Laurent  Garcin,  French  botanist  of 
the  early  part  of  the  eighteenth  century. 

Gardenia.  Cape  Jasmine.  Named  after  the  author,  Alexander  Garden  of 
South  Carolina  (1757-1829). 

Gaultheria.  Aromatic  wintergreen.  Named  for  Dr.  Gaulthier,  of  Quebec,  a, 
court  physician  about  the  middle  of  the  eighteenth  century. 

Gaylussacia.    Huckleberry.    Named  for  the  French  chemist,  Gay-Lussac. 

Gelsemium.  Yellow  Jasmine.  From  gelsomino,  the  Italian  ,name  of  Jas- 
mine. 

Genista.    Woad-waxen.    Whin.    From  the  Celtic  gen,  a  bush. 

Gentiana.  Gentian.  The  ancient  classical  name.  From  Gentius,  king 
of  Illyria,  who  according  to  Pliny  discovered  the  medicinal  property  of 
the  plant. 

Geranium.  Cranesbill.  The  Greek  name.  From  -yspavof,  a  crane.  The 
long  fruit-bearing  beak  was  thought  to  resemble  the  bill  of  the  crane. 

Geum.     Avens.     Latin  name  of  plant,  found  by  Pliny. 

Gigartina.  Sea  moss.  From  Gr.  yiyaprov,  a  grape  stone.  From  the  resem- 
blance of  the  fruit  bodies  (cystocarps),  which  appear  as  elevated 
tubercles  on  the  frond  or  thallus. 

Githago.     Corn-cockle.     Provincial  Eng.  and  Welsh  Gith. 

Glaber-bra-brum.    Smooth,  hairless  ;  referring  to  the  leaves. 

Glandulifer-a-um.     Gland-bearing.     Lat.  glandula,  gland,  -j-  fero,  to  bear. 

Glandulosus-a-um.     Full  of  glands,  glandulous. 

Glaucium.  Horned  poppy.  From  Gr.  y/lau/cdc,  glaucous.  From  the  glau- 
cous foliage. 

Globulus.  Latin  diminutive  of  globus;  a  little  ball,  globular;  referring  to 
the  button-like  form  of  the  fruit. 

'Glutinosus-a-um.  Glutinous,  viscous;  referring  to  the  resinous  leaves 
and  stems.  From  Lat.  gluten,  glue. 

Glycyrrhiza.  Liquorice.  From  Gr.  -ytivKve,  sweet,  +  p/C«,  root ;  referring 
to  the  taste  of  the  root. 

Gnaphalium.  Cudweed.  Everlasting.  Ancient  Greek  name  of  a  downy 
plant.  Probably  allied  with  KvaQaMov,  a  lock  of  wool. 

Gossypium.    Cotton.     From  Lat.  gossypion,  the  cotton-tree. 


BOTANICAL  NOMENCLATURE.  447 

Gouania.    Chew-stick. 

Gramineae.     Grass  family.     From  Lat.  gramen,  grass. 

Granatum.     Pomegranate.    The  ancient  Latin  name. 

Gratiola.    Hedge  hyssop.    From  Lat.  gratia,  favor ;  because  of  its  supposed 

medicinal  virtue. 

Graveolens.     Strong-smelling.    Lat.  gravis,  strong,  +  oleo,  to  emit  a  smell. 
Grindelia.     Gum-plant.     Tar-weed.     Named   for   Prof.  D.  H.  Grindel,   a 

Russian  botanist,  who  died  in  1836. 
Guaiacum.    Guaiac.    From  Span,  guayaco,  the  native  Haytian  name  of  the 

plant. 

Guarana.    Portuguese  name  formed  from  the  native  Brazilian  name. 
Gummifer-a-um.      Gum-producing.      From    Lat.   gummi,   gum,  -j-  fcro,    to 

bear. 

Guttifer-a-um.     Gum-exuding.     From  Lat.  gutta,  a  drop,  +  fero,  to  bear. 
Gymnocladus.    Kentucky  coffee-tree.    From  Gr.  •yv/uv6^)  naked,  -f  /^adof,  a 

branch,  the  branches  being  for  long  periods  destitute  of  spray. 
Gypsophila.     From  Gr.  yi>i/>oc,  chalk,  gypsum,  +  0^ew,  to  love. 
Habenaria.     Fringed  orchis.     From  Latin  habena,  a  thong  or  rein. 
Haematoxylon.    From  Gr.  a/^a,  blood,  -f  £v%ov,  wood ;  relating  to  the  color 

of  the  heart  wood. 
Hagenia.     Cusso.     Named  after  Dr.  K.  G.  Hagen,  German  physician  and 

apothecary    (1749-1829). 
Hamamelis.     Witch-hazel.     Ancient  Greek  name  of  a  tree  with  fruit  like 

a  pear     (//j$/f).       Of   doubtful  application,   as   the   fruit  is   a   woody 

capsule. 
Hanburii.    Latinized  genitive  from  Hanbury,  an  eminent  English  pharma- 

cognosist  and  traveller. 
Hedeoma.     Pennyroyal.    From  Gr.    f/6i>off[uie,    mint.     From    //<%,    sweet,  + 

bow,  scent. 

Hedera.     Ivy.     The  classical  Latin  name. 
Helenium.      Sneeze-weed.     Ancient   Greek   name   of   a   plant,    said   to   be 

named  after  Helenus,  son  of  Priam. 
Helianthemum.     Rockrose.     From  Gr.    fflioc,    the  sun,  -f-    avtifpn',  flower. 

The  large  flowers  open  only  once,  in  sunshine. 

Helianthus.    Sunflower.    From  Gr.  i^oc,  the  sun,  +  avttoc,  a  flower. 
Heliotropium.     Heliotrope.     Turnsole.     The  ancient  Greek  name.     From 

jy/Uoc,  the  sun,  +  rpoTny,  a  turn ;  alluding  to  the  flowering  at  the  summer 

solstice. 

Helleborus.     Hellebore.     The  ancient  classical  name. 
Hepatica.     Liver-leaf.     From  Gr.    jjirariK6st    belonging  to. the  liver.     The 

leaves  were  thought  to  resemble  the  liver  in  shape. 

Herbaceus-a-um.    Herbaceous,  grassy.    From  Lat.  herba,  grass,  herbage. 
Hesperis.     Rocket.     Greek  name  for  evening  flower.     From   effirtpa,    even- 
ing; alluding  to  the  evening  fragrance. 

Heuchera.    Alum  root.    Named  for  Prof.  J.  H.  Heucher,  who  died  in  1747. 
Hevea.    Brazilian  rubber  tree.    From  vernacular  name  heve. 


448  A  TEXT-BOOK  OF  BOTANY. 

Hibiscus.     Rose  mallow.     The  ancient  classical  name. 

Hierochloe.    Holy  grass.     From  Gr.    Iep6c,    sacred,  +  xUr),  grass.     Sweet- 
scented  grasses  strewn  before  church  doors  on  saints'  days. 
Hippocastanum.      Horsechestnut.         From    Gr.     ITTTTOC,     horse,  +  Kaaravov^ 

chestnut. 

Hirsutus-a-um.     Hirsute,  rough,  hairy. 
Hispidus-a-um.     Rough,  shaggy,  bristly. 
Hordeum.    Barley.    The  ancient  Latin  name. 

Houstonia.    Bluets.    Named  for  Dr.  William  Houston,  an  English  botanist. 
Humulus.     Hop.     Name  of  uncertain  origin.     Perhaps  from  Lat.  humus, 

ground,  alluding  to  the  fact  that  the  plant  creeps  on  the  ground  unless 

supported. 
Hydrangea.     From-  Gr.    %6opt   water,  +  ayyeiav,    a  vessel ;  from  the  shape 

of  the  capsule. 
Hydrastis.     Golden  seal.     Orange  root.     From  Gr.    vfiup,    water,  -f-  6pdu 

to  act,  accomplish.     Probably  with  reference  to  the  active  properties 

of  the  juice. 
Hydropiper.        Smartweed.        Water    pepper.      Gr.    vdupt  water,  -j-  piper, 

pepper. 
Hymenocallis.    Spider  lily.    From  Gr.  i)mfyvt    membrane,  -f  /cdAAof,  beauty ; 

alluding  to  the  crown. 
Hyoscyamus.     Henbane.    The  ancient  Greek  and  Latin  name.     From  Gr. 

vf 7  a  hog,  -f-   Ki>a[j.o^ ,    a  bean ;  said  to  be  poisonous  to  swine. 
Hypericum.     St.  John's-wort.     The  ancient  Greek  name.     Probably  from 

V7r6,  under,  -f-  kpeint],  heather. 
Icthyomethia.     Jamaica  dogwood.     From  Gr.  iffis,    a  fish,  +   piOij9   strong 

drink,  intoxicant. 
Idaeus.     From  Gr.   '/daZoc,   pertaining  to  Mt.  Ida,  near  Troy,  where  the 

raspberry  once  flourished. 

Ilex.    Holly.    The  ancient  Latin  name  for  the  holm  oak  or  holly  oak. 
Illicium.     Star  anise.     A  Latin  word   meaning  an  allurement;   alluding 

to  the  odor  and  attractive  appearance. 
Impatiens.     Touch-me-not.    A  Latin  word  meaning  "that  cannot  bear  or 

suffer,"  from  in,  not,  -f-  patiens,  enduring ;  from  the  sudden  bursting 

of  the  pods  when  touched. 
Indicus-a-um.    Pertaining  to  India. 
Inflatus-a-um.    Inflated,  swollen,  puffed  up. 
Inula.    Elecampane.    The  ancient  Latin  name. 
Ipecacuanha.     Ipecac.     Portuguese  name   from  Brazilian  ipe-kaa-guena; 

properly  a  creeping  plant  that  causes  vomiting. 

Ipomcea.    Morning  glory.    From  Gr.  tyt  In6gt  a  worm,  -f-  bpotos,  like ;  allud- 
ing to  the  twining  stems. 

Iris.     Fleur-de-lis.     Blue  flag.    From  Gr.  lpi^t   the  rainbow. 
Islandicus-a-um.    Belonging  to  Iceland. 

Isoetes.    Quillwort.     Ancient  name  used  by  Pliny,  probably  for  a  house- 
leek  or  evergreen. 


BOTANICAL  NOMENCLATURE.  449 

Iva.    Marsh  elder.    Name  of  unknown  derivation. 

Ixina.  From  native  Ixine,  at  Cumana,  Venezuela,  where  Loefling  discov- 
ered the  plant  in  1754. 

Jaborandi.    Native  name  of  a  South  American  rutaceous  shrub. 
Jalapa.     So  called  from  Jalapa,  a  town  in  Mexico,  whence  it  was  first 
obtained. 

Jateorrhiza.  Calumba.  From  Gr.  idreipa,  healing,  -f-  p/£a,  root ;  a  healing 
root. 

Jeffersonia.    Twinleaf.     Named  in  honor  of  Thomas  Jefferson. 

Juglans.  Walnut.  Name  contracted  from  Jovis  glans,  nut  or  acorn  of 
Jupiter. 

Juncus.  Rush.  Bog  rush.  Ancient  Latin  name;  from  jungo,  to  join,  the 
stems  being  used  for  bands. 

Juniperus.  Juniper.  The  classical  Latin  name;  probably  from  juvenis, 
young,  -f-  pario,  to  produce.  Youth-producing ;  in  allusion  to  its  ever- 
green appearance. 

Kalmia.     Sheep  laurel.     Named  for  Peter  Kalm,  pupil  of  Linnaeus. 

Kamala.  Hindoo  name  of  the  dusty  hairs  of  the  capsules  of  Mallotus 
Philip  pinensis,  used  as  an  orange  dye  for  silks. 

Kino.    East  Indian  name  of  the  dried  juice  of  Pterocarpus  Marsupium. 

Krameria.  Rhatany.  Named  for  Drs.  J.  G.  H.  and  W.  H.  Kramer,  Ger- 
man botanists  of  the  eighteenth  century. 

Kuhnia.  False  boneset.  Named  for  Dr.  Adam  Kuhn,  of  Philadelphia,  who 
carried  the  living  plant  to  Linnaeus. 

Kuhnistera.     Prairie  clover.     Named   from  its  resemblance  to  Kuhnia. 

Labiatae.  Mint  family.  From  Lat.  labium,  lip ;  referring  to  the  irregular 
corolla. 

Lacinaria.  Blazing  star.  From  Lat.  lacinia,  the  lappet  or  flap  of  a  gar- 
ment ;  hence  fringed,  from  the  appearance  of  the  flower  heads. 

Laciniatus-a-um.  Slashed,  having  a  fringed  border.  Lat.  lacinia,  flap, 
lappet. 

Lactuca.  Lettuce.  The  ancient  Latin  name ;  from  lac,  milk ;  referring  to 
the  milky  juice. 

Lactucarium.    The  inspissated  juice  of  the  lettuce  (lactuca). 

Lamium.  Dead  nettle.  From  Gr.  Aa^of,  throat;  alluding  to  the  ringent 
corolla. 

Lanceolatus-a-um.  Armed  with  little  lance  or  point,  lanceolate.  From 
Lat.  lance ola,  a  small  lance. 

Langsdormi.  Named  after  M.  Langsdorff,  Russian  consul  at  Rio,  1829, 
from  whom  Desfontaines  received  his  specimens. 

Laportea.  Wood  nettle.  Named  for  Frangois  L.  de  Laporte,  Count  of 
Castlenan,  an  entomologist  of  the  nineteenth  century. 

Lappa.    Burdock.    The  ancient  Latin  word  for  burr. 

Laterifolius-a-um.  Growing  by  the  side  of  the  leaf  at  its  base,  as  a 
laterifolius  flower.  Lat.  latus,  side,  -f-  folium,  leaf. 

2Q 


450  A  TEXT-BOOK  OF  BOTANY. 

Lathyrus.     Vetchling.     Everlasting   pea.     Ancient   name    of    a   plant   of 

Theophrastus. 

Lauraceae.     Laurel  family.     From  Lat.  laurus,  laurel  tree. 
Lavandula.     Lavender.     From   Lat.   lavo,  to  wash;   alluding  to  the  use 

made  of  its  distilled  water. 
Lawsonia.    Henna  plant.    Named  for  Dr.  John  Lawson,  who  lived  in  the 

eighteenth  century. 

Ledum.    Labrador  tea.    Ancient  Greek  name  of  an  Oriental  shrub. 
Leguminosae.     Pulse  family.     From  Lat.  legumen,  pulse. 
Lemnaceae.     Duckweed  family.     From  Gr.    Atum,  a  water  plant. 
Lens.     Lentil.     The  ancient  Latin  name. 
Lentiscus.    Classical  Latin  name  for  the  mastic-tree. 
Lentus-a-um.     Pliant,  flexible. 

Leonurus.    Motherwort.    From  Gr.  Muv,  a  lion,  +  ovpa,  a  tail. 
Lepidium.    Peppergrass.    Classical  name  of  a  cress.    Also  meaning  a  little 

scale;  in  allusion  to  the  fruit. 
Leptandra.     Culver's    root.     From   Gr.    ^TITOC,   slender,    +  ai%j,    avdp6sj 

man;  referring  to  the  slender  stamens. 
Leucadendron.     From  Gr.  Aewcdf,  white,  +  Se.vdpov,  a  tree. 
Levisticum.    Lovage.    Name  said  to  be  a  corruption  of  ligusticum. 
Ligusticum.     Lovage.     The  ancient  Latin  name.     Derived  from  Liguria, 

an  Italian  province  where  the  plant  abounded. 
Ligustrum.     Privet.     The  ancient  Latin   name. 
Liliaceae.    Lily  family.    From  Lat.  lilium  (Gr.  heipiov),  a  lily. 
Limonium.      Sea    lavender.      The    ancient    Greek    name;    probably    from 

heipuv.    a  meadow. 

Limonium.    Lemon.     Ital.  limone,  from  Arabic  laimun. 
Linaceae.    Flax  family.    From  Lat.  linum  (Gr.  Tiivov),  flax,  linen,  thread. 
Lippia.    Fog-fruit.    Named  for  Agostino  Lippi,  Italian  naturalist. 
Liquidambar.    Sweet  gum  tree.    From  Lat.  liquidus,  fluid,  -f-  Arabic  ambar, 

amber;  alluding  to  the  color  and  fragrance  of  the  exudation. 
Liriodendron.    Tulip  tree.    From  Gr.  faipiov,    lily,  flower,  +  66vdpovt  a  tree. 
Lithospermum.     Cromwell.     Puccoon.     The  ancient  Greek  name.     From 

Woe,  stone,  +  ffTrtppa,  seed ;  alluding  to  the  hard  nutlets. 
Lobeliaceae.     Lobelia  family.     From  lobelia.     Named   after   Matthias   de 

1'Obel,  an  early  Flemish  botanist. 
Loganiaceae.     Logania   family.     Named   after  J.   Logan,   a   distinguished 

botanist. 
Lonicera.    Honeysuckle.    Named  for  Adam  Lonitzer,  German  botanist,  who 

died  in  1586. 
Loranthaceae.        Mistletoe    family.       From    Gr.    l&pov,    a    thong,  -{-  avttoe, 

a  flower. 

Lotus.     Bird's-foot  trefoil.     An  ancient  Greek  plant  name. 
Lunaria.     Moonwort.     From  Lat.  luna,  the  moon;  alluding  to  the  silvery 

septum  of  the  fruit. 


BOTANICAL  NOMENCLATURE.  451 

Lupinus.    Lupine.    Sun-dial.    Ancient  Latin  name  of  a  plant.    From  lupus, 

a  wolf;  because  these  plants  were  thought  to  devour  the  fertility  of 

the  soil. 
Lupulus.     Diminutive  of  Lat.  lupus,  wolf;  wolfish,  because  it  chokes  the 

shrubbery  on  which  it  climbs. 

Lusitanicus-a-um.     Pertaining  to  Lusitania,  the  western  part  of  Spain. 
Luteus-a-um.   Of  or  belonging  to  the  yellow- weed  (luteum)  ;  hence  golden 

yellow,  flame-colored. 
Lychnis.     Campion.     Ancient  Greek  name  for  a  plant  with  flame-colored 

flower.     From    /lir^of,   a  light  or  lamp.  u 

Lycopodiaceae.     Club-moss  family.     From  Lycopodium,  club-moss. 
Lycopodium.     Club-moss.     From  Gr.    Awcof,    a  wolf,-}-   vrovst    a   foot;   in 

reference  to  the  appearance  of  the  shoots. 
Lycopus.    Bugleweed,  Water  horehound.    From  Gr.   Awcof,  a  wolf,  4-  7rot>f, 

a  foot;  from  a  fancied  likeness  in  the  leaves. 
Lythrum.     Loosestrife.     From  Gr.    ZvOpov,    blood;  perhaps  because  of  its 

styptic  properties. 

Macis.     Mace.     From  Gr.   fidicep,   an  Indian  spice. 
Maclura.     Osage  orange.    Named  for  William  Maclure,  an  early  American 

geologist. 

Maculatus-a-um.     Spotted,  mottled.     From  Lat.  macula,  a  spot. 
Magnolia.  Named  for  Pierre  Magnol,  professor  of  botany  at  Montpellier, 

France,  during  the  early  seventeenth  century. 
Majalis.    Emasculated.    From  Latin  majalis,  a  barren  hog. 
Majorana.     Marjoram.     Old  Eng.  majoran,  late  Latin  ma/oraca,  classical 

Latin  amaracus. 

Major-us.    Larger,  greater.    Comparative  of  magnus,  large. 
Mallotus.    Kamala.    From  Gr.//aAAwrd^  woolly,  fleecy;  the  young  branches, 

leaves  and  capsules  being  covered  with  fine  hair  or  wool. 
Malvaceae.-    Mallow  family.     From  Lat.  malva,  mallow. 
Mamillosus-a-um.      Filled    with    papillae    or    "  little   breasts."      From    Lat. 

mamilla,  little  breast,  in  allusion  to  the  stalked  cystocarps. 
Manna.     The  dried  exudation  of  Fraxinus  Ornus.     Gr.    parra,    a  grain, 

from  Hebrew  man,  gift. 
Marginalis-e.      Marginal,   belonging   to   the    margin.      From    Lat.    inargo, 

margin,  edge;  with  reference  to  the  marginal  position  of  the  sori. 
Mariana.      Carduus.      Milk    thistle,    Virgin    Mary's    thistle,    named    from 

Maria,  Latin  name  for  Mary. 
Marilandicus-a-um.     Pertaining  to  Maryland. 
Maritimus-a-um.     Belonging  to  the  sea.    From  Lat.  mare,  the  sea. 
Marmelos.    Bengal  quince.    From  Portuguese  marmelo,  quince. 
Marrubium.    Horehound.    Latin  classical  name,  derived  from  the  Hebrew 

marrob,  bitter;  a  bitter  juice. 

Marsilea.     Named  for  Aloysius  Marsili,  an  early  Italian  naturalist. 
Marsupium.    A  pouch,  bag.  Gr.  fiap^vmov;  referring  to  the  shape  of  the  fruit. 


452  A  TEXT-BOOK  OF  BOTANY. 

Mastic.     Gr.  ^aari^jf)    from    fiaado/j.at)    to  chew.     Used  in  the  East  as  a 

chewing  gum. 
Matico.    Dried  leaves  of  Piper  angustifolium.     Said  to  have  been  named 

from  a  Spanish  soldier,  who  applied  the  green  plant  to  a  wound  and 

stopped  the  bleeding. 
Matricaria.    Wild  chamomile.    From  Lat,  matrix,  the  womb ;  in  allusion  to 

its  supposed  effect  on  that  organ. 
Medicus-a-um.    Medical,  curative. 
Melaleuca.     Cajaputi.     From  Gr.   ^Aaj-,    black,  -f-  Aewcdf,  white;  the  bark 

of  the  trunk  being  black,  that  of  the  branches  white. 

Melilotus.    Sweet  clover.    From  Gr.  peht,  honey,  +  Awrof,  a  kind  of  clover. 
Melissa.     Balm.    From  Gr.  pehiaca,  a  bee ;  the  flowers  yielding  an  abund- 
ance of  honey. 
Menispermum.    Moonseed.     From  Gr.  /w^v/f,  crescent,  -j-  anepfj-a,  seed;  in 

reference  to  the  crescent-shaped  seeds. 

Mentha.     Mint.    The  ancient  Latin  name.     From  Gr.    fiivdq,  mint. 
Menyanthes.    Buckbean.    Probably  from  Gr.  fiqv,  month,  +  &v6oc,  a  flower. 

Perhaps  because  it  blooms  for  about  a  month. 

Mercurialis.    Mercury.    Ancient  Latin  name  of  a  plant;  meaning  belong- 
ing to  Mercury,  the  messenger  of  the  gods. 

Methysticum.    Kava-kava.    Gr.  ^etfuan/cof,    intoxicating;  from   /ueOv,    wine. 
Meum.    Spignel.     Bear  wort.    The  ancient  Greek  name   (^ou). 
Mezereum.     French  mezereon,  from  Persian  mazriyun. 
Microcarpus-a-um.      Having   small    fruit.      From    Gr.     fuitpog,     small,    + 

/capTTOf,    fruit. 
Mikania.     Climbing  hempwood.     Named  for  J.  G.  Mikan,  professor  in  the 

University  of  Prague,  who  died  in  1814. 

Milaceus-a-um.  Of  or  pertaining  to  millet,  Lat.  milium,  millet. 
Millef olium.    Yarrow.    The  ancient  Latin  name ;  from  mille,  thousand,  -f- 

folium,  leaf. 
Mitchella.     Partridge  berry.    Named  for  Dr.  John  Mitchell,  a  botanist  of 

Virginia,  eighteenth  century. 
Mitella.     Mitrewort.     Bishop's   cap.     Diminutive   of   Lat.   mitra,   a   cap; 

alluding  to  the  form  of  the  young  pod. 
Mollis-e.    Pliant,  soft,  mild. 
Monarda.  Horse  mint.     Named  for  Nicholas  Monardes,  Spanish  botanist 

and  author  of  the  sixteenth  century. 
Monniera.     Hedge  hyssop.     Named  for  Prof.  L.  Guillaume  le  Monnier, 

a  French  botanist  of  the  eighteenth  century. 
Monotropa.     Indian  pipe.     From   Gr.  fi6vof,    one,  -f-    rporr^,    a  turn ;   the 

summit  of  the  stem  being  turned  to  one  side. 
Montanus-a-um.     Belonging  to  the  mountain,  mountainous. 
Morus.    Mulberry.    Ancient  Latin  name  for  the  mulberry  tree. 
Mucuna.    Cowhage.    From  the  vernacular  Brazilian  name. 


BOTANICAL  NOMENCLATURE.  453 

Muricatus-a-um.     Rough  with  short,  hard  points.     Lat.  murex,  a  pointed 

rock. 
Myosotis.    Forget-me-not.     The  ancient  classical  name.     From    Gr.  ^i>£,  a 

mouse,    ovf,  wrdf,    the  ear.     From  the  short  and  soft  leaves  in  some 

species. 
Myrica.     Wax  myrtle.     Bayberry.    From  Gr.  /zup//«7,    ancient  name  of  the 

tamarisk. 

Myristica.    Nutmeg.    From  Gr.  pvpifa,  to  be  fragrant. 
Myrrha.     Myrrh.     Ancient  classical  name  for  the  balsamic  juice  of  the 

Arabian  myrtle. 

Myrtus.     Myrtle  tree.    The  ancient  classical  name. 
Napaea.     Glade  mallow.     From  Gr.  vairr],  a  woody  dell. 
Napellus.     Little  turnip.     Diminutive  of  Lat.  napus,  a  turnip. 
Narcissus.     The  ancient  Greek  name.     From    vapurj^  numbness,  because  of 

its  narcotic  properties.     Or,  according  to  others,   from  Narcissus,  a 

youth,  who  according  to  a  myth  was  changed  into  this  flower. 
Nardus.     Spikenard.     The  ancient  Greek  name. 
Nectandra.     Bebeeru.     Pichury  beans.     From  Gr.    VSKTOP,   nectar,  -f-  avyp, 

man,  nectar  stamen. 

Nelumbo.    Sacred  bean.    Lotus  lily.    From  vernacular,  Ceylon. 
Nepeta.     Catnip.     Cat  mint.     The  ancient  Latin  name. 
Neslia.    Ball  mustard.    Named  for  J.  A.  N.  de  Nesle,  French  botanist. 
Nicotiana.     Tobacco.     Named   for  Jean  Nicot,  a   French  diplomat,  who 

was  thought  to  have  introduced  tobacco  into  Europe  (1530-1600). 
Nigella.     Fennel  flower.     Diminutive  of  Lat.  niger,  black,  from  the  color 

of  the  seeds. 

Niger-gra-grum.     Black,  dark. 
Nobilis-e.    Famous,  noted,  well-born. 
Nux-vomica.    Lat.  nux,  a  nut,  and  vomo,  to  vomit. 
Nymphsea.     Yellow  pond  lily.     Ancient  Greek  name  for  the  water  lily, 

which  was  dedicated  to  the  water  nymphs. 
Nyssa.    Tupelo.     Pepperidge.    The  Latin  name  of  a  water  nymph,  nurse 

of  Bacchus;  because  the  original  species  of  the  plant  grows  in  water. 
Obtusifolius-a-um.     Having  leaves  blunted  or  rounded  at  the  end.     Lat. 

obtusus,  blunted,  -f-  folium,  leaf. 
Occidentalis-e.    Occidental.    Western. 

Odontorhizon.     Crawley-root.     From  Gr.    bdavs,    a  tooth,  -f-  P%a,    a  root. 
Odoratus-a-um.     Emitting  a   smell,   especially   sweet-smelling,   fragrant. 
CEnothera.     Evening  primrose.     An  ancient  Greek  name  of  a  plant. 
Officinalis-e.     Pertaining  to  the  shop.    From  Lat.  officina,  a  workshop. 
Oleaceae.    Olive  family.    From  Lat.  olea,  olive  tree. 
Oleum.    Gr.  IZaiov,    olive  oil;  hence  oil. 
Onoclea.     Sensitive  fern.     Ancient  Greek  name  of  a  plant. 
Operculina.    Turpeth  root.     Probably  from  Lat.  operculum,  a  covering. 
Opium.    Gr.  dirtovf  poppy  juice. 


454  A  TEXT-BOOK  OF  BOTANY. 

Opulus.    Ancient  Latin  name  of  a  kind  of  maple. 

Opuntia.     Prickly  pear.     Ancient  'Greek  name  of  a  plant,  perhaps   from 

'OroDf,  a  town  in  Locris. 

Orientalis-e.     Pertaining  to  the  Orient  or  East. 
Origanum.     Wild  marjoram.     The  ancient  Greek  name.     Probably  from 

bpoft  mountain,  -j~  -yavog,  brightness,  joy. 
Ornus.     Wild  mountain  ash.     The  classical  Latin  word.     Perhaps   from 

Gr.  fyof,    mountain. 
Osmunda.     Flowering  fern.     From  Osmunder,  Saxon  name  of  the  Celtic 

divinity,  Thor. 

Ostrya.    Hop  hornbeam.    Ironwood.    The  ancient  classical  name. 
Oxalis.    Wood  sorrel.    Ancient  classical  name ;  from  Gr.  6ft-?,    sour. 
Oxycedrus.     Prickly   cedar.     Ancient   Greek   name ;    from  6f i>f ,    sharp,  -j- 

jclrf/oof,  cedar.    Cedar  with  pointed  leaves. 
Paeonia.    Peony.    The  ancient  Greek  name.    From    llatuv,  physician  to  the 

gods. 

Palmatus-a-um.  Pertaining  to  a  palm,  like  a  palm.  From  Lat.  palina,a  palm. 
Palustris-e.     Fenny,  marshy,  swampy.     From  Lat.  palus,  a  marsh. 
Panax.    Ginseng.    Greek  name  of  a  plant.    From  Tra^,  all,  +  d/cof,  a  cure  ; 

all-healing,  panacea. 
Paniculatus-a-um.      Having    panicles.      From    Lat.    panicula,    a    tuft    or 

panicle. 

Panicum.     Panic  grass.     Ancient  Latin  name  of  Italian  panic  grass. 
Papaver.     Poppy.     The  classical  Latin  name. 

Papyrifer-a-um.     Producing  papyrus.    Lat.  papyrus,  -f-  fero,  to  bear. 
Parviflorus-a-um.     Having  small  flowers.     Lat.  parvus,  small,  -|-  fios,  a 

flower. 
Passiflora.    Passion  flower.    Adaptation  of  the  Latin  flos  passionis,  flower 

of  passion.     From  a  supposed  resemblance  of  the  parts  of  the  flower 

to  the  implements  of  the  crucifixion. 
Pauciflorus-a-um.      Having    few    flowers.      Lat.    paucus,    few,  +  ftos,    a 

flower. 
Paullinia.    Guarana.    Named  for  C.  F.  Paullini,  a  German  botanist  (1643- 

1712). 

Pedatus-a-um.     Having  pedates  or  lobes.     Lat.  pedo,  to  supply  with  feet. 
Peltatus-a-um.     Peltate  or  shield-like.     Lat.  pelta,  a  shield. 
Pcnnalifolius-a-um.    Feathered,  winged.    Lat.  pennatus,  winged,  -j-  folium, 

leaf. 

Penthorum.    Ditch  stonecrop.     From  Gr.  jr£vre,  five,  +  opof,   a  rule ;  refer- 
ring to  the  quinary  order  of  the  flower. 
Pepo.     Pumpkin.     Melon.     The  ancient  Latin  word. 

Pereirse.     Of   Pereira.     Named  in  honor  of  Jonathan   Pereira,  an  Eng- 
lish pharmacologist,  who  visited  South  America   (1804-1853). 
Perfoliatus-a-um.    Perforate.    Stem  apparently  passing  through  the  leaves. 

Lat.  per,  through,  +  folium,  leaf. 


BOTANICAL  NOMENCLATURE.  455 

Perforatus-a-um.     Perforate,  having  holes  as   if  pricked  through.     Lat. 

perforo,  to  pierce  through. 
Persea.    Avocado.    Ancient  name  of  an  Egyptian  tree  with  fruit  growing 

on  the  stem. 

Persicaria.    Lady's  thumb.    From  Lat.  persicus,  a  peach  tree. 
Petroselinum.      Parsley.      An    ancient    Greek    plant-name.      From   Trtrpo, 

a  rock,  +  aehivov,   parsley. 

Phaseolus.    Kidney  bean.    The  ancient  classical  name. 
Philadelphus.     Mock  orange  or  Syringa.     Ancient  Greek  name  of  a  sweet 

flowering  shrub  ;  applied  by  Linnaeus  to  this  genus. 
Phillipinensis-e.     Belonging  to  the  Philippine  Islands. 
Phlox.     Greek  name  of  a  plant  with  flame-colored  flowers.     From    0/U$£ 

a  flame. 
Physostigma.    Calabar  bean.    From  Gr.  ^ixra,  a  bladder,  +  <7-/;/z«,   a  mark, 

stigma. 
Phytolacca.     Pokeweed.     From  Gr.    $vT6v}   plant,  -f-  Ital.  lacca,  lake  color  ; 

alluding  to  the  coloring  matter  which  the  berries  yield. 
Picea.     Spruce.     The  classical  Latin  name  of  the  pitch-pine. 
Picrasma.     Quassia.     From  Gr.   TriKpacjuoc;,   bitterness. 
Picrotoxinum.     From  Gr.    Tiv/cpdf,    bitter,  +  Togmdv,  poison. 
Pilocarpus.     Jaborandi.     From  Gr.   TrZ/lof,   a  hair,  -f-   Kapiros,  fruit  ;   refer- 

ring to  the  shape  of  the  fruit. 
Pimenta.    Allspice.    From  Spanish  pimicnta,  allspice.    Derived  from  Latin 

pigmentum,  spice. 
Pimpinella.    Pimpernel.   Said  to  be   formed   from   Lat.   bipinnula,  equiva- 

lent to  bipennis,  two-winged  ;  referring  to  the  bipinnate  leaves. 
Pinus.    Pine.    The  ancient  Latin  name.    Probably  akin  to  pinna,  a  feather. 
Piper.     Pepper.     The  classical  Latin  name. 
Piperitus-a-um.     Peppery,  pungent.     Lat.  piper,  pepper. 
Pipsissewa.     Chimaphila.     An  American  Indian  name. 
Piscipula.     From  Lat.  piscis,  fish. 
Pistacia.     Pistachio.     The  ancient  classical  name. 
Planifolius-a-um.     Having  flat  leaves.     Lat.  planus,  flat,  plane,  -f-  folium, 

leaf. 

Plantago.     Plantain.     The  ancient  Latin  name. 
Podophyllum.     Mandrake.     From  Greek    71-0%,   foot,  +  QVAAOV]  referring 

to  the  foot-like  leaves. 
Podostemon.    Riverweed.    From  Gr.    iroif,  foot,  -f-  ffTqpuv,  thread,  stamen  ; 

the  two  stamens  being  apparently  raised  on  a  stalk  by  the  side  of  the 

ovary. 
Polemonium.    Greek  valerian.     An  ancient  Greek  name  of  a  plant.     From 


war. 

Polygala.     Milkwort.     From   Gr.      iroMyafov,     the   ancient   name. 
much,  +  }'a?rz,  milk. 


45^  A  TEXT-BOOK  OF  BOTANY. 

Polygamus-a-um.     Having  some  perfect  flowers  and  others  with  stamens 
only,  or  pistils  only,  on  the  same  plant ;  polygamous.    From  Gr.    iro/.vs, 
much,  -f-  j-afji£uf  to  marry. 
Polygonatum.     Solomon's  seal.     Ancient  Greek  name  of  a  plant.     From 

iroMc,  much,  many,  +  y6w,  yovaror,  knee;  having  many  joints. 
Polygonum.     Knotweed.     The  ancient  classical  name.     From  Gr. 

much,  many,  +  y6vvf  knee*;  having  many  knots  or  joints. 
Polypodium.     Polypody.     The  ancient  Greek  name.     From    TTOAVC,    much, 

many,  -f-  novg,    foot ;  alluding  to  the  branching  rootstock. 
Polyporus.     Agaric.     From  Gr.    iroM>£,    many,  +  v6pogt    a  pore ;   referring 

to  the  porous  texture  of  the  plant. 
Populus.     Poplar.    Aspen.    The  classical  Latin  name. 

Potentilla.  Cinquefoil.  Five-finger.  Name  is  a  diminutive  form  of  Lat. 
potens,  powerful;  from  the  reputed  medicinal  powers  of  one  of  the 
species. 

Pratensis-e.     Growing  in  meadow-land.     Lat.  pratum,  meadow. 
Precatorius-a-um.     Imploring,  beseeching.     From  Lat.  precor,  to  pray ;  in 

allusion  to  the  use  of  the  seeds  as  beads  in  rosaries. 
Primula.     Primrose.     Cowslip.     The  name  is  a  diminutive  of  Lat.  primus, 

first ;  from  the  flowering  of  the  primrose  in  early  spring. 
Procumbens.    Lying  on  the  ground.    From  Lat.  procumbo,  to  incline  for- 
ward. 
Prunifolius-a-um.     Having   leaves    resembling    those    of    the    plum    tree. 

From  Lat.  prunus,  plum  tree,  -|-  folium,  leaf. 
Prunum.    Plum.     Classical  Latin  name  for  the  fruit. 
Prunus.     Plum,  cherry.    Classical  Latin  name  for  the  plum  tree. 
Pruriens.     Itching.     From  Lat.  prurio,  to  itch ;  in  reference  to  the  hairs, 

which  occasion  an  intolerable  itching. 

Psyllium.     Flea-seed.     Ancient  Greek  name  for  fleawort. 
Psoralea.      From  Gr.  ^wpa/leof,  scurfy ;  in  reference  to  the  glandular  dots 

on  the  calyx  and  pods. 

Ptelea.    Hop-tree.    Ancient  Greek  name  for  the  elm. 
Pteris.    Brake  or  Bracken.    Ancient  Greek  name  for  a  kind  of  fern.    From 

irrepov,    a  wing ;  alluding  to  the  pinnate  or  feathery  fronds. 
Pterocarpus.    From  Gr.  irrepov,  a  wing,  -f-  K.apir6$,    fruit ;  in  allusion  to  the 

winged  legumes. 
Puber-a-um.     Downy. 

Pubescens.    Downy,  hairy,  woolly.    From  Lat.  pubesco,  to  become  downy. 
Pulegioides.    Like  fleabane.    From  Lat.  pulegium  (Gr.     i/wA/uov),    fleabane, 

+   -o-ei6w,    resembling;  in  allusion  to  the  appearance  and  odor. 
Pulicaria.    Fleawort.    The  ancient  Latin  name. 
Pulmonaria.     Lungwort.     From  Lat.  pulmonarius,  beneficial  to  the  lungs. 

From  its  supposed  curative  properties. 

Pulsatilla.    Pasque  flower.    From  Lat.  pulso,  to  strike,  agitate ;  of  uncertain 
application. 


BOTANICAL  NOMENCLATURE.  457 

Punica.     Pomegranate.     From  Lat.  punicum,  pomegranate  tree. 

Purpureus-a-um.     Purple-colored. 

Purshianus-a-um.     Adjective   formed   from  Purshia.     Named   for   Fred. 

Pursh,  a  German  botanist  and  author  of  Flora  America  Septentrionalis. 
Pyrethrum.     Pellitory.     Feverfew.     Ancient  Greek  name  for  a  hot,  spicy 

plant. 

Pyrus.    Pear,  Apple.    Ancient  Latin  name  for  the  pear  tree. 
Quassia.    Named  for  a  negro,  Quassy  or  Quash,  who  prescribed  this  remedy 

as  a  specific. 
Quebracho-bianco.     From   Sp.   quebrantar,  to  break,   -f-   hacha,   an  axe; 

in  allusion  to  the  hard  and  tough  bark.    Blanco,  white. 
Quercus.    Oak.    The  classical  Latin  name. 
Quillaja.     Soap  bark.     From  vernacular  quillai,  Chili. 
Racemosus-a-um.     Having  racemes  or  clusters. 
Radicans.    Rooting.    From  Lat.  radico,  to  take  root;  alluding  to  the  fact 

that  the  stems  send  out  roots. 
Ranunculus.     Crowfoot.     Buttercup.     The  Latin  name  for  a  little  frog; 

some  species  being  aquatic. 
Raphanus.    Radish.    The  classical  name.    From  Gr.  pa,  quickly,  +  fyaivofiai, 

to  appear;  alluding  to  the  rapid  germination. 
Repens.     Creeping.     From  Lat.  repo,  to  creep. 
Reptans.    Creeping.    From  Lat.  repto,  to  creep. 
Reseda.    Mignonette.    From  Lat.  resedo,  to  calm,  heal ;  from  its  supposed 

sedative  properties. 

Reticulatus-a-um.    Reticulate,  net-like.    Lat.  retia,  a  net;  leaf -veins  form- 
ing a  net-work. 

Rhamnus.     Buckthorn.     The  ancient  classical  name. 
Rhaponticus-a-um.      Rhapontic.      From    Lat    Rha,    the    Volga    river,  -\- 

ponticus,  pertaining  to  the  Pontic  or  Black  Sea.    The  rhubarb  growing 

on  the  banks  of  the  Rha. 
Rheum.    Rhubarb.     From  Lat.  Rha,  the  river  Volga,  on  whose  banks  the 

plant  grew. 
Rhododendron.    Rose-bay.    The  ancient  name.    From  Gr.  p66ov,  a  rose,  + 

divdpov,  a  tree. 

Rhus.      Sumach.      The    ancient    classical    name. 
Ribes.     Currant.     Gooseberry.     From  Arabic  ribds,  a  plant  with  an  acid 

juice. 

Ricinus.    Castor  bean.    The  ancient  Latin  name. 
Robinia.    Locust.    Named  for  John  and  Vespasian  Robin,  royal  gardeners 

of   Paris,  seventeenth  century. 

Robustus-a-um.     Robust,  strong,  oaken.     Lat.  robur,  oak. 
Rosa.    Rose.    The  ancient  Latin  name. 
Roseus-a-um.     Rose-colored,  rosy.     Lat.  rosa,  a  rose. 
Rosmarinus.    Rosemary.    From  Lat.  ros,  dew,  +  marinus,  belonging  to  the 

sea;  from  its  maritime  habitat. 


458  A  TEXT-BOOK  OF  BOTANY. 

Rostratus-a-um.    Beaked,  curved,  rostrate.    Lat.  rostrum,  a  beak. 

Rotundifolius-a-um.  Having  round  leaves.  Latin  rotundus,  round,  -f- 
folium,  leaf. 

Ruber-ra-rum.    Red,  ruddy. 

Rubus.    Bramble.    Blackberry.    Ancient  Latin  name,  akin  to  ruber,  red. 

Rugosus-a-um.     Wrinkled,  creased.     Lat.  ruga,  a  wrinkle. 

Rumex.     Dock  Sorrel.    The  classical  Latin  name. 

Ruta.     Rue.    The  ancient  classical  name. 

Sabadilla.  Cevadilla.  From  Span,  cevadilla.  Probably  from  Lat.  cibus, 
food,  though  the  seeds  are  poisonous. 

Sabal.     Palmetto.    From  vernacular,  Mexico  or  South  America. 

Sabina.  From  Lat.  Sabinus,  of  the  Sabines ;  a  people  of  Italy  who  used  the 
juniper  as  an  incense. 

Saccharum.     The  classical  name  for  sugar. 

Saigonicus-a-um.     Of   Saigon,   a   city   and   province  in   southern   Annam. 

Salix.    Willow.    The  classical  Latin  name. 

Salvia.  Sage.  The  ancient  Latin  name.  From  salvo,  to  save ;  because  of 
its  supposed  healing  qualities. 

Sambuciis.  Elder.  The  old  Latin  name,  perhaps  from  Gr.  aapftvKq,  a  musi- 
cal instrument. 

Sanctus-a-um.     Holy,  sacred,  consecrated. 

Sanguinaria.  Bloodroot.  From  Lat.  sanguinarius,  bloody;  from  the  color 
of  the  juice. 

Sanicula.     Black  snakeroot.     Sanicle.     From  Lat.  sano,  to  heal. 

Santalinus-a-um.     Of  the  sandal-tree,  of .  sandal-wood.     Gr.    oavrakov     the 

> 

sandal-tree. 

Santalum.    Sandal-wood.    The  ancient  Greek  name  for  sandal-tree. 
Saponaria.     Soapwort.     From  Lat.  sapo,  soap;  the  juice  forming  a  lather 

with  water. 

Sarracenia.    Pitcher  plant.    Named  for  Dr.  Michel  Sarrasin,  of  Quebec. 
Sassafras.    The  Spanish  name.     Probably  a  modification  of  saxifrage. 
Sativus-a-um.    Cultivated.    Propagated  by  seed. 
Scammonia.     Scammony.     Classical  name  of  a  plant, 
Scandens.     Climbing.     Lat.  scando,  to  climb. 
Scilla.    Squill.    The  ancient  Greek  name  for  the  medicinal  squill. 
Scirpus.     Rush.     The  ancient  Latin  name. 
Scolopendrium.       Adder's    tongue.       The    ancient     Greek    name.      From 

<7Ko/o7rw5pa,  .the  centipede ;  alluding  to  the  sori. 
Scoparia.     Broom-weed.     From  Lat  scopa,  a  broom. 
Scutellaria.    Skullcap.    From  Lat.  scutclla,  a  dish ;  alluding  to  the  calyx. 
Secale.    Rye.     Latin  name  for  a  kind  of  grain.     From  seco,  to  cut. 
Sedum.    Stonecrop.    Orpine.    Latin  name  of  a  houseleek.    From  scdeo,  to 

sit;  alluding  to  the  manner  in  which  the  plants  attach  themselves  to 

walls  and  rocks. 
Semecarpus.    Cashew-nut.    From  Gr.  cny//a,  a  mark,  +  nap^of;,  fruit. 


BOTANICAL  NOMENCLATURE.  459 

Sempervirens.  Evergreen.     Lat  semper,  always,  +  vireo,  to  be  green. 
Senecio.    Groundsel.    Ragwort.    Squaw- weed.    From  Lat.  senex,  old  man  ; 

alluding  to  the  hoariness  of  some  species. 
Senega.     Seneca  root.     From  the  Seneca  tribe,  North  American  Indians, 

who  used  it  as  a  remedy  for  snake  bites. 
Senegal.     Name  of  a  country  and  river  in  W.  Africa.     Habitat  of  the 

plant  Acacia  Senegal. 

Senna.    Senna  leaves.    Name  derived  from  Arabic  Sana  or  sena. 
Serenoa.     Saw  palmetto.     Named  for  Prof.  Sereno  Watson  of  Harvard 

University   ( 1826-1892) . 

Serotinus-a-um.     Late,  backward ;  relating  to  the  flowers  and  fruit. 
Serpentaria.      Snakeroot.      The    ancient    Latin    name.      From    scrpcns,    a 

serpent. 

Serrulatus-a-um.    Serrulate,  notched.    From  Lat.  serrula,  a  saw. 
Sesamum.     Sesame.    The  classical  name  of  the  sesame. 
Siliqua.    The  classical  Latin  name  for  a  pod. 

Silphium.    Rosin  weed.    Ancient  Greek  name  of  some  resinous  plant. 
Simaba.     Cedron.     From  vernacular  name,  Guiana. 
Sinapis.     Mustard.    The  ancient  Greek  name  was  oivcnrt.     The  Latin  had 

both  forms,  siuapis  and  sinapi. 

Sinensis-e.    More  commonly  Chinensis.    Pertaining  to  China. 
Sisymbrium.    Hedge  mustard.    The  ancient  Greek  name  of  a  sweet-scented 

plant. 
Smilax.     Green  brier,   cat  brier.     An   ancient   Greek  name   for   the  yew, 

and  for  several  plants. 

Socotrinus-a-um.    Of  Socotra,  an  island  east  of  Africa. 
Solanum.     Nightshade.     The  ancient  Latin  name. 

Solidago.    Goldenrod.    From  Lat.  solido,  to  make  whole,  to  heal ;  in  refer- 
ence to  its  supposed  healing  properties. 
Somnifer-a-um.     Sleep-producing.     From  Lat.  somnus,  sleep,  -f-  fcro,  to 

bear,  bring. 

Sorbilis-e.    Sorbile,  fit  to  be  drunk  or  sipped.    Lat.  sorbeo,  to  suck. 
Sorbus.    Mountain  ash.    The  ancient  Latin  name. 
Sorghum.     Derivation   uncertain.     Probably   of    Chinese   or   East    Indian 

origin. 

Spicatus-a-um.    Supplied  with  spikes,  spicate. 
Spigelia.     Pink  root.     Worm-grass.     Named  for  Adrian  von  der  Spiegel, 

Flemish  botanist  of  the  seventeenth  century. 
Spiraea.     Hardback.     Meadow-sweet.     The  ancient  Greek   name.     From 

ffTreifia,    a  coil  or  twist ;  from  the  twisting  of  the  pods  in  some  species. 
Squarrosus-a-um.     Scabby,  scurfy,  ragged. 
Staphisagria.      Stavesacre.      From    Gr.  <rrap/Y,   raisin,  +    «yp«of,  wild ;    the 

fruit  clusters  resemble  wild  grapes. 
Stillingia.    Named  for  Dr.  B.  Stillingfleet,  English  botanist  of  the  eighteenth 

century. 


460  A  TEXT-BOOK  OF  BOTANY. 

Stramonium.     Stinkweed.    From  French  stramoine. 

Striatus-a-um.  Marked  with  lines  or  ridges,  striate ;  Lat.  strio,  to  groove, 
mark. 

Strophanthus.  From  Gr.  ytrrpwtft,  a  turn,  twist,  +  avOoc,  a  flower ;  from 
the  twisted  and  tailed  lobes  of  the  corolla. 

Strychnos.     The  ancient  Greek  name  of  a  poisonous  plant. 

Styraciflua.  A  tree  producing  storax.  From  Lat.  styrax,  storax,  +  fluo, 
to  flow. 

Styrax.     Storax.    The  ancient  Greek  name  of  the  storax  tree. 

Succirubra.  From  Lat.  succus,  juice,  +  ruber,  red; — the  sap  becomes  red 
on  exposure. 

Swertia.  Chiretta.  Named  for  Emanuel  Sweert,  herbalist  of  the  seven- 
teenth century. 

Sylvaticus-a-um.  )  _. 

0  ,  }•  Pertaining  to  the  woods.    Lat.  silva,  a  wood,  forest. 

Sylvesins-e.  ) 

Symphoricarpos.      Snowberry.      From    Gr.      avfi^opeu^    to   bring   together, 

+  Kfl/o7T(5f ,  fruit ;  from  the  clustered  berries. 
Symphytum.    Comfrey.    The  ancient  Greek  name.    From    avpQi.'u,  to  cause 

to  grow  together ;  because  of  its  reputed  healing  virtues. 
Syringa.     Lilac.     From   Gr.    avpiyZ,    a  pipe ;   in  reference  to  the  tubular 

corolla,  or  to  the  use  of  the  wood  for  pipe-stems. 
Tabacum.    Tobacco.    Span,  tabaco,  from  the  Indian  word  denoting  the  tube 

or  pipe  used  in  smoking  the  plant. 
Tamarindus.   Indian  date.    From  Arabic  tamarhindi,  tamar,  a  dried  date,  -\- 

Hind,  India. 
Tanacetum.     Tansy.     From  the  French  name,  tanaisie,  derived  from  Gr. 

atidvaroc;,    immortal. 
Taraxacum.     Dandelion.     From   rapdaau,  to  stir  up,  disorder;  in  allusion 

to  its  medicinal  properties. 

Terebinthina.     Turpentine.     From  Gr.  T{p£{3(vOost  the  turpentine  tree. 
Teucrium.     Germander.     Named  for  Teucer,  king  of  Troy. 
Thalictroides.      Resembling    thalictrum.      From    Gr.     ttahiKrpov,   -f-   o-e«tyf, 

like. 

Thalictrum.     Meadow  rue.     Ancient  Greek  name  of  a  plant. 
Thea.     Tea.     French  The,  from  Chinese  tsha. 
Theobroma.     Cacao.     From  Gr.  0eoff  a  god,  -+-  ppij/ta,  food. 
Thuja.     Arbor  Vitae,   Cedar.     Ancient   Greek  name   for  an   African  tree 

with  sweet-smelling  wood. 
Thymus.    Thyme.    Ancient  Greek  name.     From  Ovw,  to  sacrifice ;  alluding 

to  the  sweet  odor.  . 

Tiarella.      False   mitrewort      Coolwort.     Diminutive    of    Lat.    tiara,   cap; 

from  some  fancied  resemblance  of  the  capsules. 
Tilia.  Linden.  Basswood.  The  classical  Latin  name. 
Tinctorius-a-um.  Pertaining  to  dyeing,  containing  coloring  matter.  Lat. 

lingo,  to  dye,  color. 


BOTANICAL  NOMENCLATURE  .  461 

Tinctorum.     Of  the  dyers.     Genitive  plural  of  tinctor,  a  dyer. 

Toluifera.    Balsam  tree.    Said  to  be  formed  from  Tolu  (Santiago  de  Tolu, 

in  New  Granada),  whence  balsam  was  first  brought,  -f-  fero,  to  bear. 
Tomentosus-a-um.    Tomentose.    Woolly.    Lat.  tomentum,  stuffing. 
Toxicodendron.      From    Gr.    ro£//c<n',     poison,  -j-    di-vdpov,    tree ;    poisonous 

shrubs. 
Tradescantia.      Spiderwort.      Named    for   John   Tradescant,    gardener   to 

Charles  I. 
Tragacantha.     Tragacanth.     The  ancient  Greek  name  for  the  Astragalus. 

From  r/jdyoc,  a  goat,  +  d/coi^a,    a  thorn ;  in  allusion  to  the  character 

of  the  gummy  exudation. 
Tragopogon.     Salsify.     Goat's   beard.     Ancient   Greek  name   of   a  plant. 

From    rpriyoc,  a  goat,  -f-  TTCJ/WP,  beard  ;  alluding  to  the  pappus. 
Triandrus-a-um.     Having  three  stamens.     Gr.  Tptis,  three,  -f-  avr/pt  man. 
Tricolor.    Having  three  colors,  tricolored.    Lat.  trcs,  three,  -{-  color,  color. 
Tricuspidatus-a-um.    Ending  in  three  points.    Lat.  tricuspis,  three-pointed. 
Trifolium.     Clover.     Trefoil.     The  ancient  Latin  name.     Three-leafed. 
Trilisa.    Vanilla-leaf.     Deer's  tongue.     Name  an  anagram  of  Liatris. 
Trillium.     Wake  robin.     Birthroot.     From  Lat.  ires,  three ;  all  the  parts 

being  in  threes. 

Triphyllus-a-um.     Having  three  leaves.     Gr.  r/?pZc,  three,  0ti/Uoi>,  leaf. 
Triticum.     Wheat.     The  ancient  Latin  name.     From  tritus,  past  participle 

of  tero,  threshed  or  ground. 
Trivialis-e.     Common,  trivial.     Lat.  tres,  three,  -f-  via,  road  ;  three  roads, 

growing  along  many  roads. 

Tsuga.     Hemlock.     The  Japanese  name  of  one  of  the  species. 
Tuberosus-a-um.     Tuberous.     Lat.  tuber,  lump,  tumor. 
Turpethum.    Turpeth.     From  Persian  tirbid,  a  cathartic ;  turbad,  a  purga- 
tive root. 
Tussilago.    Coltsfoot.    The  ancient  Latin  name.    From  tussis,  a  cough,  for 

which  the  plant  is  a  reputed  remedy. 

Ulmaria.     Queen  of  the  meadow.     From  ulmus,  elm ;  hence  elm-like. 
Ulmus.    Elm.    The  classical  Latin  name. 
Umbellatus-a-um.     Umbellated,  like  an  umbel.     Lat.  umbella,  little  shade, 

umbel. 
Umbellularia.     Bay-laurel.      From   umbellula,   little   umbel,    a    late    Latin 

diminutive  of  umbella. 

Uniflorus-a-um.     Bearing  one  flower  only.     Lat.  unus,  one,  -f-  flos,  flower. 
Urginea.     Squill.     Sea  onion.     From  Lat.  urgeo,  to  press ;  alluding  to  its 

flattened  seeds. 

Urtica.     Nettle.     The  ancient  Latin  name. 
Usitatissimus-a-um.    Most  useful,  common,  familiar ;  superlative  degree  of 

usitatus. 

Ustilago.     Smut,  Bunt.    An  ancient  Latin  name  of  a  plant. 
Uva-ursi.    Bearberry.    From  Latin  uva,  a  grape,  +  ursi,  of  a  bear. 


462  .  A  TEXT-BOOK  OF  BOTANY. 

Valeriana.    Vale-rian.    Probably  from  Lat.  valeo,  to  be  strong. 

Vanilla.  From  Spanish  vainilla,  diminutive  of  vaina,  a  sheath,  pod;  be- 
cause its  seeds  are  contained  in  little  pods. 

Variifolius-a-um.  With  varying  leaves.  Lat.  varius,  various,  changing,  -f 
folium,  a  leaf. 

Venenosus-a-um.     Poisonous,  deadly.     Lat.  vcnenum,  poison. 

Veratrum.     False  hellebore.     The  classical  Latin  name. 

Veronica.     Speedwell.     Dedicated  to  St.  Veronica. 

Versicolor.  Having  various  colors.  Lat.  vcrto,  to  turn,  change,  +  color, 
color. 

Verticillatus-a-um.  Disposed  in  a  whorl.  Lat.  verticillus,  diminutive  of 
vertex,  a  whirl;  referring  to  the  leaves  or  flowers. 

Verus-a-um.    True,  genuine,  original. 

Viburnum.    Black  haw.    Arrow-wood.    The  ancient  Latin  name. 

Victorialis.     Ancient  Latin  name  of  a  plant. 

Villosus-a-um.     Hairy,  shaggy,  villous. 

Vinifer-a-um.    Wine-producing.     Lat.  vinum,  wine,  +  fcro,  to  bear. 

Viola.     Violet.     Heart's  ease.     The  ancient  Latin  name  of  the  genus. 

Virginianus-a-um. )  _ 

,,.     .   .  }•  Of  or  belonging  to  Virginia. 

Virgmicus-a-um.    J 

Viridiflorus-a-um.     Having  green   flowers.     Lat.   viridis,   green,  +  flos,   a 

flower. 

Viridis-e.     Green. 

Virosus-a-um.    Having  a  bad  odor,  fetid.    Lat.  virus,  an  offensive  smell. 
Vitis.    Grape.    The  classical  Latin  name. 

Vouacapoua.     Araroba  tree.     From  vernacular  name,  Central  America. 
Vulgaris-e.     Common,  general,  ordinary. 
Wisteria.    Named  in  honor  of  Prof.  Caspar  Wistar,  distinguished  anatomist 

of  Philadelphia. 
Xanthium.     Clotbur,  Cocklebur.     Greek  name  of  some  plant  used  to  dye 

•  the  hair.    From   gav66?, }  yellow. 
Xanthoxylum.     Prickly  Ash.     From   Gr.     gavOds,   yellow,  -f-    gbfav,   wood ; 

referring  to  the  color  of  the  roots. 

Zea.    Maize.    Indian  corn.    Ancient  classical  name  for  a  kind  of  grain. 
Zeylonicus-a-um.    Of  or  belonging  to  Ceylon. 
Zingiber.    Ginger.    The  ancient  Greek  name. 


CHAPTER  V 

CLASSIFICATION  OF  ANGIOSPERMS  YIELDING  ECONOMIC 

PRODUCTS 

IN  this  chapter  will  be  given  in  natural  sequence  a  list  of  the 
principal  orders  of  plants  that  yield  medicinal  and  other  economical 
products.  While  great  stress  will  be  laid  upon  the  plants  used  in 
medicine,  yet  considerable  attention  will  also  be  given  to  the  other 
economic  substances  furnished  by  the  angiosperms,  as  food- 
products,  fibers,  coloring  principles,  woods,  and  timbers,  as  well 
as  to  the  plants  commonly  cultivated  for  ornamental  purposes. 
It  will  be  found  that  the  number  of  plants  useful  to  man  is  a  very 
large  one,  being  derived  from  all  the  important  families,  so  that  in 
their  consideration  the  student  will  gain  a  rather  comprehensive 
view  of  the  entire  group. 

A.    CLASS    MONOCOTYLEDONE.E. 

The  Monocotyledons  are  mainly  distinguished  as  follows :  The 
embryo  has  only  one  cotyledon  ;  the  leaves  are  mostly  scattered  and 
parallel-veined ;  the  fibrovascular  bundles  of  the  stem  are  of  the 
closed  type,  and  the  flowers  are  typically  trimerous. 

I.    ORDER  PANDANALES. 

This  order  includes  members  which  are  aquatic  or  marsh  plants, 
with  narrow,  elongated  leaves  and  very  small,  imperfect  and 
incomplete  flowers  in  spikes  or  heads. 

The  TYPHACE;E  or  Cat-tail  family  has  the  flowers  borne  in 
densely  crowded  terminal  spikes,  the-staminate  flowers  being  at 
the  upper  end  of  the  spike,  while  the  pistillate  flowers  which  are 
beneath  are  more  persistent. 

The  SPARGANIACE^E  or  Bur-reed  family  have  the  flowers  borne 
in  densely  globose  heads,  the  staminate  heads  being  rather  small 
and  near  the  upper  part  of  the  stalk,  while  the  pistillate  heads  are 
larger  and  situated  a  short  distance  below  the  staminate  ones 
(Fig.  252). 

463 


464 


A  TEXT-BOOK  OF  BOTANY. 


FlG.  252.  Bur-reed  (Sparganium  eurycarpum),  a  perennial  plant  flowering  throughout 
the  summer  and  growing  on  the  borders  of  ponds,  lakes,  and  rivers  throughout  the  United 
States.  It  grows  to  a  height  of  8  to  12  dm.,  and  produces  long,  ribbon-like  leaves.  The 
flowers  are  in  heads,  becoming  bur-like  from  the  divergent  beaks. — After  Brown. 


CLASSIFICATION  OF  ANGTOSPERMS.  465 


FlG.  253.  Arrow-head  (Sagittaria  latifolia),  a  common  marsh  or  aquatic  plant  and 
very  widely  distributed.  The  leaves  are  variable,  but  almost  always  sagittate.  It  produces 
naked  scapes  which  are  sheathed  by  the  bases  of  the  petioles;  the  white  flowers  are  produced 
all  summer. — After  Troth. 

30 


466  A  TEXT-BOOK  OF  BOTANY. 

IT.    ORDER  NAIADALES. 

This  order,  as  with  other  rather  primitive  orders,  is  made  up 
mostly  of  aquatic  and  marsh  plants,  the  flowers  frequently  being 
spicated. 

The  NAIADACE^E  or  Pond-weed  family  comprises  such  genera 
as  Potamogeton,  the  common  Pond-weed,  and  Zostera,  or  Eel- 
grass,  which  is  extremely  common  in  bays  and  estuaries  in  all 
parts  of  the  country,  and  in  many  places  its  collection  forms  an 
active  industry.  It  is  used  in  upholstery  work  and  as  a  packing 
material. 

To  the  ALISMACE^:  or  Water- Plantain  family  belong  Alisma, 
the  Water- Plantain,  and  Sagittaria,  or  Arrow-head,  which  is  a  very 
attractive  plant  (Fig.  253) .  Of  the  latter  there  are  a  large  number 
of  species  which  are  widely  distributed. 

III.    ORDER   GRAMINALES   OR   GLUMIFLOR^. 

This  order  is  composed  of  the  two  families,  grasses  (Gram- 
ineae)  and  sedges  (Cyperacese). 

a.  GRAMINE^:  OR  GRASS  FAMILY.— The  plants  of  this 
family  are  nearly  all  herbs  having  cylindric,  generally  hollow 
culms  with  swollen  nodes.  The  leaves  are  exactly  alternate,  and 
have  long  sheaths  which  are  split  or  seldom  closed,  tubufar,  and 
nearly  always  with  a  distinct  ligule.  The  flowers  are  mostly 
hermaphrodite  and  borne  in  spikelets  with  alternate  floral-leaves, 
the  spikelets  themselves  being  borne  in  spicate  or  paniculate  in- 
florescences. Each  spikelet  (Figs.  255,  256)  consists  of  two 
(seldom  more)  empty  glumes,  which  are  the  lowest  floral-leaves 
in  each  spikelet ;  a  varied  number  of  flowering  glumes,  frequently 
awned  or  toothed,  are  situated  inside  the  empty  glumes,  and 
each  of  which  subtends  a  short  branch  (the  rhachilla),  the  latter 
bearing  an  adorsed  fore  leaf  (the  pale),  which  is  generally  two- 
keeled  and  two-toothed,  enclosing  two  minute  scales  (lodiculesj 
and  the  flower.  The  flower  has  mostly  three  stamens  (there 
being  six  stamens  in  Oryza  and  Bambusa),  with  the  anthers  versa- 
tile, and  a  simple  gynsecium  consisting  of  one  carpel  having  two 
styles  and  a  plumose  stigma.  The  ovary  is  unilocular  with  one 
ascending  or  pendulous  ovule.  The  fruit  is  a  grain  or  caryopsis, 


CLASSIFICATION  OF  ANGIOSPERMS. 


467 


the  seed  being  always  firmly  united  with  the  thin  pericarp  (except 
in  Sporobolus,  Eleusine,  etc.).  The  embryo  is  situated  at  the 
base,  on  the  outer  convex  surface  of  the  seed,  outside  the  endo- 
sperm. On  germination  the  cotyledons  remain  in  the  seed. 

The  endosperm  contains  numerous  starch  grains  and  oil,  while 
the  gluten  layer  around  the  endosperm  contains  proteins.  The 
number  of  layers  of  gluten-  or  aleurone-containing  cells  varies  in 
the  different  cereals.  In  corn,  wheat,  and  rye  it  consists  of  but 
a  single  layer ;  in  oat  (Fig.  247)  and  rice,  of  i  or  2  layers  ;  while  in 
barley  it  is  made  up  of  2  to  4  layers. 

The  Grasses  comprise  about  3500  species  and  are  distributed 
in  all  parts  of  the  world.  While  most  of  the  plants  are  grass-like, 


FIG.  254.  Diagrams  of  cross-sections  of  monocotyledonous  flowers:  t,  stem  of  plant; 
f,  bract;  s,  sepals  or  outer  circle  of  perianth;  p,  petals  or  inner  circle  of  perianth;  a,  stamens; 
c,  ovary.  A,  regular  flower  of  the  lily;  B,  irregular  flower  of  iris.  C,  flower  of  an  orchid, 
in  which  1  is  the  position  of  the  lip  and  S  8  of  the  two  staminodes. — After  Warming. 

still  some  of  them,  as  the  bamboos  of  the  Tropics,  become  quite 
tall,  having  woody  siliceous  stems  and  bearing  many  branches  in 
the  axils  of  the  leaves.  The  grasses  yield  the  cereal  grains  forming 
so  large  a  proportion  of  the  food  of  man,  and  forage  constituting 
the  food  of  many  of  the  lower  animals.  The  following  are  some  of 
the  important  cereals:  Wheat  (Triticum  sativum  and  its  varie- 
ties), corn  (Zea  Mays),  oat  (Avena  sativa),  rice  (Oryza  sativa), 
barley  (Hordeum  sativum  and  its  varieties),  rye  (Secale  cereale}. 
A  number  of  the  species  yield  a  sweet  cell-sap  from  which  cane 
sugar  is  made,  of  which  the  most  important  are  the  sugar  cane 
(Saccharum  oMcinarum)  and  sorghum  (Andropogon  arundina- 
ceus saccharatus  and  other  varieties).  (Consult  pp.  148,  156,  198.) 


468 


A  TEXT-BOOK  OF  BOTANY. 


A  large  number  of  the  grasses  are  used  in  medicine,  one  of 
which,  couch-grass  (Agropyron  repens),  is  official. 

Agropyron  repens  is  a  common  perennial  grass,  forming  slen- 
der jointed  rhizomes,  by  means  of  which  the  plant  is  extensively 
propagated ;  the  culms  vary  from  one  to  four  feet  in  height,  the 
spikelets  are  3-  to  7-flowered ;  and  the  empty  glumes,  5-  to  7-nerved, 
acute  or  with  a.n  awn-like  apex. 

Hordeum  sativum  is  an  annual  grass  with  the  flowers  in  ter- 


F!G.  255.  Wheat  (Triticum):  A,  zigzag  axis  or  rachis  of  ear  showing  the  notches 
where  the  spikelets  were  inserted;  B,  an  entire  spikelet;  C,  a  flower  with  the  pales;  D,  a 
flower  without  the  pales,  showing  the  lodicules  at  the  base;  E,  glume;  F,  outer  pale;  G, 
inner  pale;  H,  fruit  (caryopsis) ;  I,  longitudinal  section  of  fruit. — After  Warming. 

minal  cylindrical  spikes  resembling  wheat.  The  spikelets  are  ses- 
sile, i-flowered,  and  usually  in  clusters  of  three  on  opposite  sides 
of  the  notched  rachis.  The  empty  glumes  are  long  and  narrow, 
forming  a  kind  of  involucre  around  the  spikelet.  It  is  supposed 
that  Hordeum  sativum  is  a  cultivated  form  of  H.  spontaneum 
growing  in  the  countries  between  Asia  Minor  and  other  parts  of 
Western  and  Southwestern  Asia.  Three  important  varieties  are 
distinguished,  depending  upon  the  number  of  rows  of  grains  in 


CLASSIFICATION  OF  ANGIOSPERMS.  469 

the  ear.  H.  sativum  distichon  includes  the  plants  having  2-rowed 
ears,  and  these  are  chiefly  grown  in  Middle  Europe  and  England. 
H.  sativum  hexastichon  includes  the  plants  having  the  grains  in 
6  rows,  these  having  been  cultivated  since  prehistoric  times  and 
furnishes  the  winter  barley.  H.  sativum  vulgare  includes  the 
plants  in  which  the  grains  are  in  6  irregular  rows,  and  these 
are  cultivated  in  northern  temperate  regions.  The  latter  plant 
is  cultivated  in  the  United  States  and  furnishes  the  spring  or 
summer  barley,  largely  used  in  the  preparation  of  malt. 

Zea  Mays  (Indian  Corn)  is  a  cereal  plant  probably  indigenous 
to  Central  Mexico.     It  is  extensively  cultivated  in  the  United 


FIG  256.  Diagrammatic  outline  of  a  spikelet:  nY,  lower  glume;  <f>  Y,  upper  glume; 
nl,  outer  pale;  <f>  I,  inner  pale;  1,  1,  lodicules;  st,  stamens;  I-I,  main  axis;  II,  lateral  axes 
or  branches.—After  Warming. 

States  and  other  parts  of  the  world  for  its  grain.  From  a  multi- 
ple, primary,  somewhat  fibrous  root  arise  one  or  more  erect  simple 
culms,  which  are  grooved  on  alternate  sides  in  the  successive 
internodes  and  from  the  nodes  of  which  arise  aerial  secondary 
roots.  The  leaves  are  alternate  and  consist  of  3  parts:  (a)  a 
blade,  which  is  long,  broadly-linear  and  tapering  toward  the  apex, 
the  tip  being  pendulous;  (b)  a  lower  sheathing  portion  which 
is  open;  and  (c)  a  short,  translucent,  somewhat  hairy  ligule, 
situated  between  the  sheath  and  the  blade.  The  flowers  are 
monoecious,  the  staminate,  which  are  arranged  in  a  terminal  pan- 
icle, maturing  first;  the  pistillate  occur  in  axillary  spikes,  the 
axes  of  which  constitute  the  corn  cob.  They  are  enclosed  in 


470  A  TEXT-BOOK  OF  BOTANY. 

spathe-like  bracts  or  husks,  from  which  the  long  filiform  styles 
(p.  178)  protrude.  The  grain  is  somewhat  ovate  or  triangular, 
flattened,  pointed  at  the  base,  grooved  on  one  side,  indicating  the 
position  of  the  embryo,  from  10  to  15  mm.  long  and  about  10  mm. 
broad,  more  or  less  translucent,  and  varies  in  color  in  the  different 
varieties.  The  constituents  of  the  corn  grain  are  50  to  75  per  cent, 
of  starch ;  about  10  per  cent,  of  proteins ;  4.29  per  cent,  of  a  fixed 
oil;  about  5  per  cent,  of  sugar,  and  1.29  per  cent,  of  ash. 

There  are  a  large  number  of  varieties  and  sub-varieties  of  Zca 
Mays,  some  of  the  former  being  ranked  as  species.  The  follow- 
ing well-defined  varieties  may  be  mentioned : 

1 i )  Zea  Mays  everta,  to  which  belong  the  POP-CORNS.    The 
size  of  the  ears  and  grains  is  about  one-half  or  less  that  of  the 
other  corns ;  the  grains  have  a  more  or  less  translucent  and  horny 
endosperm,  the  cells  of  the  latter  containing  numerous  compactly 
arranged  polygonal  starch  grains,  which  are  from  7  to   10  ^  in 
diameter  and  have  a  central  rarefied  area  from  2  to  7  /x  in  diam- 
eter.    It  is  owing  to  the  structure  of  the  starch  grains  that  the 
peculiar  popping  of  the  corn  grains  results  when  they  are  heated. 
Heating  the  corn  grains  at  145°  to  160°  C.  for  from  4  to  10  min- 
utes causes  the  bursting  of  the  starch  grains,  and  at  the  same  time 
a  rupture  of  the  cells  and  splitting  of  the  pericarp  into  4  parts. 
The  white  appearance  of  the  popped  grains  is  due  to  the  inclusion 
of  air  in  the  bursted  cells.    During  the  heating  the  starch  is  con- 
verted into  a  soluble  form,  and  this  gives  popped  corn  its  nutritive 
value.    Some  of  the  flint  and  dent  corns  show  a  similar  tendency 
to  pop  when  heated,  but  it  is  only  in  those  parts  of  the  endo- 
sperm that  are  horny  and  the  cells  of  which  contain  compactly 
arranged  polygonal  starch  grains  in  which  the  rarefied  area  is  at 
least  from  one-tenth  to  one-fifth  the  diameter  of  the  entire  grain. 
Pieces  of  the  pop-corn,  as  well  as  the  horny  portions  of  some  of 
the  flint  and  dent  corns,  will  pop  as  readily  as  the  whole  grains. 

(2)  Zea  Mays  indentata  yields  the  DENT  or  FLINT  CORNS,  the 
grains  of  which  have  a  corneous  (horny)  endosperm  on  the  sides 
and  are  indented  at  the  summit,  owing  to  the  shrinking  of  the 
cells  which  contain  more  cell-sap  and  less  compactly  arranged 
starch  grains. 

The  starch  grains  in  the  cells  of  the  horny  endosperm  resem- 


CLASSIFICATION  OF  ANGIOSPERMS, 


.471 


FIG.  257.  Carex  lurida,  one  of  the  Sedge  family  (Cyperacece),  found  throughout  the 
summer  in  swamps  and  wet  meadows  in  the  eastern  and  central  United  States.  It  is  a 
perennial  grass-like  herb  with  triangular  culms,  3-ranked  leaves,  and  with  2  to  4  spikes  of 
flowers.  The  genus  is  a  vast  one  of  more  than  a  thousand  species,  widely  distributed  and 
most  abundant  in  the  temperate  zones. — After  Troth. 

ble  those  of  pop-corn,  but  the  starch  grains  in  the  other  cells  are 
more  or  less  rounded  or  slightly  polygonal,  and  vary  from  5  to  25  /x. 
in  diameter;  the  central  rarefied  area  is  either  wanting  or  usually 
not  more  than  2  /x  in  diameter. 

(3)   Zea  Mays  saccharata  yields  the  SUGAR  CORNS.    While  .the 


472  A  TEXT-BOOK  OF  BOTANY. 

grains  are  more  or  less  translucent  and  horny,  they  have  a 
wrinkled  or  shrivelled  surface.  The  cells  of  the  endosperm  con- 
tain gum-like  substances  and  a  relatively  small  number  of  nearly 
spherical  starch  grains  from  4  to  io/x  in  diameter. 

BROOM  CORN  (Andropogon  arundinaceus  vulgar -e)  is  a  plant 
which  is  cultivated  for  the  panicles  or  seed  heads,  which  are  used 
in  the  manufacture  of  brooms.  This  plant  differs  from  the  other 
species  of  Andropogon  in  that  the  branches  of  the  panicles  are 
longer,  straighter,  and  stronger,  forming  a  so-called  "  brush." 

Quite  a  number  of  the  grasses  contain  odorous  principles,  as 
Andropogon  citratus,  which  yields  lemon-grass  oil;  A.  Schcenan- 
thus,  which  yields  gingergrass  or  geranium-grass  oil;  A.  squar- 
rosus,  the  rhizome  of  which  is  known  as  Vetiver.  Coumarin  is 
found  in  Vanilla  grass  (Anthoxanthum  odoratum)  and  white  or 
Dutch  clover  (Hierochlcc  odorata).  Some  species  of  Stipa  are 
used  in  the  manufacture  of  paper  (Alfa  or  Esparto)  in  North 
Africa  and  Spain. 

b.  CYPERACE^E  OR  SEDGE  FAMILY.— These  plants  are 
all  herbaceous,  the  majority  being  perennial  (seldom  annual). 
The  rhizomes  are  mostly  sympodial  (being  monopodial,  however, 
in  certain  Carices),  and  the  stems  are  mostly  solid  and  triangular, 
without  swollen  nodes.  The  leaves  are  grass-like,  generally 
arranged  in  three  rows,  and  the  sheath  is  closed,  being  mostly 
without  ligules.  The  flowers  may  be  hermaphrodite  or  unisexual, 
sometimes  dioecious,  and  arranged  in  spikes  or  racemes.  The 
perianth  is  wanting  or  only  represented  by  6  bristles,  or  by  an 
indefinite  number  of  hairs.  The  number  of  stamens  is  3,  with  the 
anthers  attached  by  their  bases  to  the  filament.  The  gynaecium 
consists  of  2  to  3  carpels,  with  one  style  divided  into  2  or  3 
branches,  and  provided  with  papillae.  The  fruit  is  a  nut,  whose 
seed  is  generally  united  with  the  pericarp.  The  embryo  is  small 
and  is  centrally  situated  at  the  base  of  the  seed,  being  surrounded 
by  the  endosperm.  On  germination,  the  cotyledon  is  freed  from 
the  seed. 

A  number  of  the  sedges  yield  food  products,  as  the  rhizomes 
of  Cyperus  esculentus  and  Eleocharis  tuberosa,  the  latter  of  which 
is  used  in  the  manufacture  of  starch  in  China  and  India.  Quite 
a  number  of  species  of  Scirpus,  Cyperus,  Carex,  etc.,  are  used  in 


CLASSIFICATION  OF  ANGIOSPERMS.  4/3 

medicine.  Various  species  of  Cyperus  (C.  scariosus,  of  the  East 
Indies,  and  C.  pertenuis,  of  India)  yield  ethereal  oils  and  are  used 
in  making  perfumery.  Cyperus  Papyrus  is  used  in  medicine  and 
also  furnished  the  paper  of  the  Ancients. 

IV.    ORDER    PRINCIPES. 

In  this  order  is  included  that  interesting  group  of  tropical 
and  sub-tropical  plants  the  PALMS  (Palmae).  They  are  arbores- 
cent, having  simple  unbranched  trunks  which  are  terminated  by 
clusters  of  leaves,  in  the  axils  of  which  flowers  are  produced.  The 
leaves  are  pinnate  (Feather  Palms)  or  palmate  (Fan  Palms) 
and  often  very  large.  The  petiole  is  well  developed,  with  an  am- 
plexicaul,  more  or  less  fibrous  sheath.  The  inflorescence  is  usually 
lateral,  in  some  cases  forming  a  large  spadix  with  a  woody,  boat- 
shaped  spathe.  In  comparison  the  individual  flowers  are  very 
small.  The  fruit  is  either  a  berry,  as  in  the  Date  palm,  or  a  drupe, 
as  in  the  Cocoa-nut  palm,  generally  I -seeded  and  with  a  large 
horny  or  bony  endosperm,  as  in  the  Date  palm  (p.  135)  and 
Phytelephas  macrocarpa,  the  latter  of  which  yields  vegetable  ivory, 
used  in  the  making  of  buttons  (Fig.  258). 

The  fruit  of  the  saw  palmetto  [Serenoa  (Sabal)  serrulata], 
one  of  the  fan  palms,  is  official.  The  saw  palmetto  is  characterized 
by  having  a  creeping,  branching  root-stock  or  rhizome,  one  end 
of  which  rises  a  short  distance  above  ground,  this  portion  being 
surmounted  by  a  dense  crown  of  leaves.  The  petioles  are  slender 
and  spinose  on  the  edges ;  the  blade  is  fan-shaped  and  consists  of 
a  number  of  palmate  divisions  which  are  slightly  cleft  at  the  apex. 
The  inflorescence  is  densely  tomentose  and  shorter  than  the  leaves. 
The  fruit  is  a  i -seeded  drupe. 

The  palms  yield  a  number  of  useful  products.  The  Betel-nut 
palm  (Areca  Catechu)  produces  a  seed  having  medicinal  proper- 
ties (Fig.  259).  The  seeds,  known  as  ARECA  NUT,  are  20  to  25 
mm.  long,  conical,  grayish-brown,  with  numerous  spiral,  reddish 
veins,  heavy,  hard,  somewhat  aromatic,  astringent,  and  slightly 
acrid.  They  contain  about  o.i  per  cent,  of  an  oily  liquid  alkaloid, 
arecoline,  which  chemically  and  in  its  physiological  action  resem- 
bles pelletierine ;  14  per  cent,  of  tannin,  resembling  catechutannic 
acid ;  gallic  acid ;  a  red  coloring  principle ;  and  14  per  cent,  of  a 


474 


A  TEXT-BOOK  OF  BOTANY. 


fixed  oil.  They  also  contain  3  other  alkaloids:  arecaine,  arecai- 
dine,  and  guvacine,  but  these  do  not  seem  to  give  the  drug  its 
properties. 

CARNAUBA-WAX  is  obtained  from  the  Carnauba-palm  of  Brazil 
(Copernicia  cerifera).  The  wax  exudes  from  the  surface  of  the 
young  leaves  and  is  obtained  by  boiling  them  with  water.  DRAGON'S 


FIG.  258.  Vegetable  Ivory,  the  endosperm  of  the  seeds  of  a  Central  American  palm 
(Phytelephas  macrocarpa).  The  fruits  are  produced  near  the  ground,  are  nearly  globular, 
measuring  about  i  meter  in  circumference,  and  weigh  about  14  pounds  each.  They  are 
covered  with  a  woody  spinose  wall  (A),  and  enclose  a  number  of  drupes  (B),  each  of  which 
contains  a  single  hard  seed  (C).  The  latter  contains  a  hard,  white,  fine-grained  endosperm 
(D);  it  is  used  in  making  small  articles  of  turnery,  as  buttons,  etc. — Reproduced  by  permis- 
sion of  The  Philadelphia  Commercial  Museum. 

BLOOD,  a  bright  red  resinous  substance,  is  obtained  from  the  juice 
of  the  fleshy  fruit  of  Calamus  Draco.  It  consists  chiefly  of  resin, 
some  tannin,  and  about  3  per  cent,  of  benzoic  acid. 

The  Oil  palm  (Elccis  guineensis)  of  equatorial  West  Africa 
yields  a  drupe  with  an  oily  sarcocarp,  from  which,  by  means  of 
pressure  or  boiling  with  water,  PALM  OIL  is  obtained.  The  Cocoa- 
nut  palm  (Cocos  nucifera)  yields  the  COCOA  NUT  of  the  market, 


CLASSIFICATION  OF  ANGIOSPERMS.  475 

and  is  probably  one  of  the  most  useful  palms  to  the  natives,  fur- 
nishing, as  it  does,  food,  clothing,  utensils  of  all  kinds,  building 
materials,  etc.  The  Sago-palms  (Metroxylon  Rumphii  and  M. 
Iccve)  yield  SAGO,  which  is  prepared  by  washing  out  the  starch 
from  the  cut  stems  and  subsequently  heating  it.  A  tree  15  years 
old  yields  from  three  to  four  hundred  kilograms  of  sago  starch. 
The  Date  palm  (Phoenix  dactylifera)  yields  the  DATES  of  the 


FlG.  259.  A  number  of  Areca-nut  palms  (Areca  Catechu)  growing  in  Ceylon.  The 
stems  are  slender,  attaining  a  height  of  25  meters  or  more,  with  a  diameter  of  3  to  4  dm. 
and  bearing  a  cluster  of  leaves  at  the  summit.  The  palm  is  also  known  as  the  Betel-nut 
palm,  and  is  extensively  cultivated  throughout  tropical  India. — Reproduced  by  permission 
of  The  Philadelphia  Commercial  Museum. 

market,  and  it  is  interesting  to  note  that  since  very  early  times 
the  fruits  produced  by  the  growers  in  the  Orient  have  been  the 
result  of  artificial  or  hand-pollination. 

V.    ORDER    ARALES    OR    SPATHIFLOR/E. 

This  order  includes  two  families  which  are  markedly  different 
in  their  habits:  (i)  The  Aracese,  which  are  rather  large  herbs 
with  an  inflorescence  known  as  a  spadix  and  consisting  of  a  fleshy 


476 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  260.  Fruits  and  iiowers  of  several  of  the  palms.  A,  cluster  of  flowering  spikes 
of  the  cocoanut  palm  (Cocos  nucifera);  B,  number  of  the  young  fruits  of  the  cocoanut 
palm;  C,  cluster  of  the  ovoid  fruits  of  the  betel-nut  palm  (Areca  Catechu);  D,  compound 
inflorescence  of  drooping  spikes  of  the  kittul  (Ijittool)  palm  (Caryota  urens);  E,  large  clusters 
of  deltoid  fruits  of  kittul  palm. — Reproduced  by  permission  of  the  Philadelphia  Commercial 
Museum. 

The  cocoanut  palm  yields  a  larger  number  of  economic  products  than  any  other  tree 
in  the  world;  the  fruit  is  edible  and  yields  the  cocoanut  oil,  the  sap  produces  an  alcoholic 
beverage,  the  leaves  are  used  for  making  useful  articles,  and  the  wood  is  employed  in  cabinet 
making. 

The  Betel-nut  palm  yields  a  number  of  valuable  products,  the  most  important  being 
the  seed,  which  is  not  only  used  to  stimulate  digestion,  but  is  used  in  many  religious  cere- 
monies, as  well  as  in  regulating  the  intercourse  of  the  more  polished  classes  of  the  East. 
The  base  of  the  leaf  stalks  of  the  kittul  palm  yield  a  fiber  which  is  elastic,  shows  considerable 
tenacity,  and  is  used  in  the  making  of  brushes  for  brewers'  use. 


CLASSIFICATION  OF  ANGIOSPERMS.  477 


FIG.  261.  Jack-in-the-Pulpit,  or  Indian  Turnip  (Aris&ma  triphyllum) ,  a  very  common 
perennial  herb  growing  in  woods  and  thickets  of  the  eastern  and  central  parts  of  the  United 
States  and  Canada,  and  characterized  by  i  or  2  leaves  which  are  divided  into  3  ellfptical- 
ovate,  pointed  leaflets  and  a  characteristic  spathe  of  a  greenish  color,  frequently  purple- 
striped  and  curving  in  a  broad  flap  over  the  top  of  the  club-shaped  spadix.  The  plant 
produces  a  turnip-shaped  corm  with  an  intensely  acrid  juice. — After  Troth. 


478 


A  TEXT-BOOK  OF  BOTANY. 


spike,  which  is  subtended  or  enclosed  by  a  large  bract  known  as 
a  spathe,  as  in  the  Calla-lily,  where  it  is  large  and  white,  and  (2) 
the  Lemnaceae  or  duckweed  family,  which  is  composed  of  minute, 


FlG.  262.  Skunk  Cabbage  (Symplocarpus  fcttidus),  a  perennial  herb  producing  a  very 
thick  rhizome,  from  which  arise  in  the  early  spring  the  flowers  crowded  on  a  spadix  sur- 
rounded by  a  large,  shell-like  spathe  which  barely  rises  out  of  the  ground  and  is  striped  or 
spotted  with  purple  and  yellowish-green.  These  are  followed  by  a  cluster  of  ovate,  cordate 
leaves  becoming  3  to  6  dm.  long.  In  the  illustration  are  shown  4  of  the  spathes,  the  one  at 
the  left  being  cut  open  to  show  the  globular  or  ovoid  spadix,  and  a  single  leaf  unfolding. — 
After  Troth. 

floating,  thalloid  plants  that  develop  one  or  more  flowers  on  the 
margin  or  upper  surface  of  the  thallus. 

ARACE^E  OR  ARUM  FAMILY.— The  plants  belonging  to 
this  family  are  perennial  herbs  with  tuberous  or  fleshy  rhizomes 


CLASSIFICATION  OF  ANGIOSPERMS. 


479 


and  simple  or  compound  leaves  which  are  usually  long-petioled. 
The  spadix  is  densely  flowered,  the  staminate  flowers  being  above 
and  the  pistillate  below  on  the  same  axis,  or  the  plants  are  wholly 
dioecious.  The  perianth  when  present  consists  of  4  to  6  scale-like 
segments.  Frequently  the  spadix  is  subtended  or  enclosed  by  a 
more  or  less  showy  spathe.  The  fruit  is  usually  a  berry,  some- 
times a  utricle. 


FIG.  263.  Water  Arum  (Calla  palnstris) ,  showing  portion  of  rhizome,  the  broadly 
ovate  and  cordate  leaves,  and  the  inflorescence,  which  consists  of  a  cylindrical  spadix  and 
an  elliptical  spreading  spathe. 

A  number  of  the  plants  of  this  family  have  medicinal  proper- 
ties, and  one  of  them  yields  the  unofficial  drug  CALAMUS.  The  drug 
is  derived  from  sweet  flag  (Acorus  Calamus),  a  plant  common 
in  swamps  and  along  streams  in  the  Eastern  United  States,  and 
characterized  by  its  long,  narrow,  linear,  bilateral  leaves,  which 
are  from  6  to  18  dm.  in  height  and  about  25  mm.  in  width.  The 
inflorescence  is  a  spike-like  spadix  having  greenish-yellow  flowers. 

Many  of  the  Araceae  possess  an  acrid  juice.     The  acridity  is 


480  A  TEXT-BOOK  OF  BOTANY. 

probably  due  either  to  saponin  or  an  acrid  volatile  principle  rather 
than  to  raphides  of  calcium  oxalate.  Frequently  these  principles 
are  dissipated  or  destroyed  on  cooking,  and  the  plants  are  then 
used  as  food,  as  the  WATER  ARUM  (Calla  palustris),  which  on 
account  of  its  acrid  principles  is  used  as  a  remedy  for  snake  bites 
when  in  the  fresh  condition,  but  which  on  drying  loses-  its  acridity 
and  being  rich  in  starch  is  used  as  a  food  (Fig.  263).  To  this 
family  also  belong  Jack-in-the-pulpit,  or  INDIAN  TURNIP  (Ari- 
sama  triphyllum),  the  acrid  corm  of  which  is  used  in  medicine 
(Fig.  261)  ;  SKUNK  CABBAGE  (Symplocarpiis  fcetidus),  the  fetid 
rhizome  of  which  has  medicinal  properties  (Fig.  262).  A  number 
of  plants  of  the  Arum  family  are  rich  in  starch,  as  the  tubers  of 
Xanthosoma  edule  of  Surinam,  which  contain  62  per  cent,  of 
starch. 

VI.    ORDER    XYRIDEALES    OR    FARINOSE. 

The  plants  are  mostly  perennial  herbs  of  tropical  and  sub- 
tropical America.  The  order  includes  a  number  of  families, 
among  which  is  BROMELIACE^E,  to  which  the  pineapple  (Ananas 
sativus)  belongs.  PINEAPPLE  is  a  native  of  Brazil  and  is  now  cul- 
tivated in  warm  countries  of  the  eastern  and  western  hemispheres. 
The  fruit  contains  a  proteolytic  enzyme  resembling  trypsin  and 
also  a  milk-curdling  ferment.  The  bast  fibers  of  the  leaves  are 
used  for  textile  purposes.  Some  of  the  Bromeliaceae  are  epi- 
phytic (air-plants),  the  best  known  member  being  probably  the 
FLORIDA  MOSS  (Tillandsia  usneoides),  which  is  used  in  upholstery 
(Fig.  264). 

The  family  Commelinaceae  is  represented  in  the  United  States 
by  Commelina  or  day-flower,  some  species  of  which  have  medic- 
inal properties.  The  roots  of  some  tropical  species  contain  saponin, 
as  C.  deficiens,  of  Brazil.  The  rhizomes  of  a  number  of  species 
of  Commelina  contain  notable  quantities  of  starch  and  are  edible. 
The  spiderworts  (Tradescantia)  common  in  rich  soil  in  the 
United  States,  and  the  Wandering  Jew  (Tradescantia  Zebrina) 
commonly  cultivated  as  an  ornamental  plant,  also  belong  to  this 
family.  To  the  PONTEDERIACE^:  belong  several  perennial  aquatic 
or  bog  plants,  whose  leaves  are  usually  thick  or  in  some  cases  long 
and  grass-like.  The  flowers  are  frequently  arranged  in  Spikes 
subtended  by  leaf -like  spathes  (Fig.  265). 


CLASSIFICATION  OF  ANGIOSPERMS. 


481 


482 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  265.  Pickerel  Weed  (Pontederia  cor  data),  a  common  aquatic  herb  growing  along 
the  margin  of  slow  streams.  It  is  a  very  hardy  plant  occurring  far  north  and  grows  best  in 
water  ten  or  twelve  inches  deep.  It  produces  long-petioled  leaves  and  a  single  stem  bearing 
a  spike  of  violet-blue,  ephemeral  flowers. — After  Troth. 


CLASSIFICATION  OF  ANGIOSPERMS.  483 

I 


FIG.  266.  Small  Solomon's  Seal,  also  commonly  known  as  true  Solomon's  Seal  (Poly- 
gonatum  biflorum).  It  is  a  perennial  herb  with  lance-oblong,  sessile  leaves,  in  the  axils  of 
which  are  usually  two  nodding  greenish  flowers.  The  plant  grows  in  moist  woods  or  wooded 
hillsides,  and  receives  its  common  name  from  the  creeping  knotted  rhizomes,  on  the  upper 
surface  of  which  are  usually  one  or  more  prominent  circular  scars,  formed  upon  the  decay 
of  the  aerial  shoots. — After  Biown. 


484 


A  TEXT-BOOK  OF  BOTANY 


FIG.  267.  False  Solomon's  Seal  or  False  Spikenard  (Smilacina  racemosa),  a  perennial 
herb  with  a  somewhat  stout  stem,  a  number  of  alternate  parallel-veined  leaves  and  a  terminal 
raceme  of  whitish,  sometimes  fragrant,  flowers.  It  forms  a  horizontal  knotted  rhizome,  on 
the  upper  surface  of  which  are  found  circular  scars.  It  may  be  found  growing  in  under- 
brush in  moist  woods. — After  Brown. 


CLASSIFICATION  OF  ANGIOSPERMS.  485 

VII.    ORDER    LILIALES    OR    LILIIFLORvE. 

The  plants  of  this  order  are  mostly  perennial  herbs  with  rhi- 
zomes, tubers,  bulbs,  or  fibrous  roots.  The  leaves  are  parallel- 
veined. 

a.  LILIACE^E  OR  LILY  FAMILY.— The  plants  are  the 
most  typical  of  the  Monocotyledons.  They  are  scape-like  herbs 
with  bulbs ;  the  flowers  are  symmetrical,  and  the  perianth  is  parted 
into  6  more  or  less  distinct  segments  (Fig.  123)  ;  the  anthers  are 
introrse.  The  ovary  is  free,  3-locular,  with  a  single  style,  and  the 
fruit  is  a  3-locular,  loculicidally  dehiscent  capsule. 

The  Liliaceae  is  one  of  the  most  important  families,  containing 
about  2500  species,  many  of  which  are  of  great  economic  interest. 
Quite  a  number  are  cultivated  on  account  of  the  beauty  and  fra- 
grance of  their  flowers.  Among  the  latter  are  the  hyacinth,  lily, 
lily-of-the-valley,  tuberose,  tulip,  and  yucca.  Of  those  yielding 
food  products  we  have  asparagus,  being  the  young  shoots  of 
Asparagus  officinalis.  The  edible  bulbs  include  the  onion  (Allium 
Cepa],  garlic  (Allium  sativum),  the  leek  or  scullion  (Allium 
Porrum),  and  chives  (Allium  Schcenoprasum).  A  number  of 
the  Liliacese  are  among  the  common  wild  flowers,  as  swamp  pink 
(Fig.  272),  bellwort  (Uvularia),  lily  (Lilium),  dog's-tooth  violet 
(Erythronium),  Star  of  Bethlehem  (Ornithogalum),  False  Solo- 
mon's Seal  (Fig.  267),  True  Solomon's  Seal  (Fig.  266),  Indian 
Cucumber- root  (Medeola),  colic-root  (Fig.  271),  cat  brier 
(Smilax),  etc.  The  following  plants  are  of  medicinal  interest : 

Veratrum  viride  is  a  plant  2  to  8  feet  high,  which  is  charac- 
terized by  the  broad,  clasping,  strongly  plicate  leaves,  and  by  hav- 
ing the  flowers  in  large  terminal  panicles  (Fig.  268).  The  plant 
is  found  in  swamps  and  wet  woods  in  the  United  States  in  spring 
and  early  summer.  The  rhizome  is  upright,  and  it  with  the  roots 
is  used  in  medicine.  The  plant,  including  the  rhizome,  closely 
resembles  the  Veratrum  album  of  Europe. 

Colchicum  autumnale. — This  is  the  autumnal-flowering  colchi- 
cum,  a  perennial  herb  but  a  few  inches  high  which  arises  from  a 
corm  and  bears  proportionately  large  lilac-colored  flowers.  The 
fruit  consists  of  3  follicles  containing  numerous  seeds.  The  corm 
and  seeds  of  this  and  other  species  of  Colchicum  are  used  in 


486 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  268.     Flowering  specimen  of  Veratrum  tiride,  showing  the  spreading,  spike-like 
racemes  and  the  parallel-veined  leaves. 


CLASSIFICATION  OF  ANGIOSPERMS.  487 

medicine.  Among  the  species  yielding  large  corms  and  extensively 
cultivated  is  Colchicum  Burmanii  (Fig.  269). 

Aloe  species. — The  stems  are  about  a  meter  high  and  bear  at 
the  summit  a  cluster  of  thick,  succulent  leaves  which  are  lance- 
olate and  spinous-toothed  (Fig.  270).  The  inflorescences  are  in 
long  spikes  which  are  quite  showy  and  characteristic  for  the  differ- 
ent species.  Aloe  Perryi,  which  yields  the  SOCOTRINE  ALOES, 
possesses  leaves  with  white  spines  and  flowers  that  are  orange-red 
or  scarlet  at  the  base,  the  stamens  being  unequal ;  Aloe  vera,  which 
yields  the  BARBADOES  or  CURACAO  ALOES,  has  leaves  with  yellow 
or  reddish  spines  and  yellow  flowers  in  which  the  stamens  are  as 
long  as  the  corolla ;  Aloe  ferox  and  some  other  African  species, 
which  yield  CAPE  and  UGANDA  ALOES,  have  flowers  in  close  spikes, 
the  petals  being  white  and  marked  by  green  lines,  and  the  stamens 
much  longer  than  the  corolla.  The  inspissated  juice  is  official 
in  all  the  pharmacopoeias. 

Urginea  maritinia,  which  yields  the  drug  squill,  is  character- 
ized by  its  large,  onion-like  bulb,  from  which  arise  ten  to  twenty 
broadly  lanceolate,  grayish-green  leaves ;  and  by  having  the  in- 
florescence in  long  spikes  consisting  of  whitish  flowers  which  have 
a  distinctly  purple  stripe  on  each  division  of  the  perianth. 

Convallaria  majalis  or  Lily-of-the-valley  is  a  plant  which  is 
well  known.  It  produces  a  raceme  of  delicately  odorous  white 
flowers  and  beautiful  oblong  leaves  with  prominent  parallel  veins. 
The  rhizome  and  roots  are  official. 

Smilax  species. — The  drug  sarsaparilla  is  yielded  by  at  least 
four  different  species  of  Smilax.  These  are  mostly  vines  with 
woody  or  herbaceous,  often  prickly  stems  and  leaves  with  petioles 
which  have  a  pair  of  persistent  tendril-like  appendages.  The 
flowers  are  small,  mostly  greenish,  dioecious  and  in  axillary  umbels. 
The  fruit  is  a  globose  berry.  Not  a  great  deal  is  known  of  the 
species  which  yield  the  drug,  with  the  exception  of  Smilax  medica, 
which  yields  the  Mexican  or  Vera  Cruz  sarsaparilla.  In  Smilax 
medica  the  leaves  vary  from  more  or  less  cordate  to  auriculate- 
hastate;  in  Smilax  officinalis,  which  yields  the  native  Jamaica 
sarsaparilla,  they,  are  ovate,  as  they  are  also  in  Smilax  papyracea, 
which  yields  Para  sarsaparilla.  The  Jamaica  Sarsaparilla,  official 
in  the  British  Pharmacopoeia,  is  obtained  from  plants  of  Smilax 


488  A  TEXT-BOOK  OF  BOTANY. 

ornata  growing  in  Costa  Rica  and  subsequently  shipped  to  Jamaica. 
Nothing  is  known  of  the  plant  yielding  Honduras  sarsaparilla, 
although  this  drug  has  been  in  use  for  nearly  four  centuries.  It 


FIG.   269.     Floweiing  plant  of  Colchicum  Burmami,  a  form  producing  very  large  corms  a.nd 
extensively  cultivated  in  Holland. 

is  said  to  be  derived  from  Smilax  officinalis.  The  sarsaparilla 
plants  have  short  rhizomes  which  give  rise  to  long  roots,  which 
are  the  part  used  in  medicine. 

A  DRAGON'S   BLOOD,   resembling  that   derived   from   Calamus 


CLASSIFICATION  OF  ANGIOSPERMS.  489 

Draco,  is  obtained  from  Dracccna  Draco,  a  tree  growing  in  the 
Canary  Islands.  Some  of  the  trees  of  this  species  are  of  historic 
interest,  as  the  dragon  tree  of  Orotava,  which  is  46  feet  in  circum- 
ference at  the  base. 

A  number  of  the  plants  of  this  family  contain  saponin,  as  the 
species  of  Smilax.  Some  contain  coniferin  and  vanillin,  as  Aspar- 
agus officirtalis.  Some  of  the  group  contain  glucosidal  principles 
which  under  the  influence  of  ferments  yield  ethereal  oils  contain- 


FlG.  270.  A  field  of  Aloe  plants,  growing  in  the  Riversdale  District,  Cape  Colony. 
The  stems  are  simple,  with  one  or  more  clusters  of  leaves;  the  latter  are  from  3  to  6  dm.  in 
length,  fleshy  and  very  thorny-prickly  at  the  margin. — Reproduced  by  permission  of  the 
Philadelphia  Commercial  Museum. 

ing  sulphur,  as  the  various  species  of  Allium.  Garlic  (Allium 
sativum)  contains  a  glucoside,  allisin,  which  on  hydrolysis  with  an 
oxidase  (allisin)  forms  the  essential  oil  of  garlic.  A  number  also 
are  quite  poisonous  when  fresh  but  edible  when  cooked. 

b.  AMARYLLIDACE^E .  OR  AMARYLLUS  FAMILY.— 
This  group  is  of  special  interest  because  it  includes  the  Agave 
or  Century  plant.  This  is  a  characteristic  genus  of  plants  of  the 
hot  and  arid  regions  of  North  America.  The  best  known  of  these 


490 


A  TEXT-BOOK  OF  BOTANY. 


is  the  CENTURY  PLANT  (Agave  americana),  which  is  one  of  the 
most  important  economic  plants  of  Mexico.  The  stem  axis  of 
the  plant  is  very  short  and  the  thick,  fleshy  leaves  form  a  tuft  at 


FIG.  271.  Plant  of  Aletris  farinosa  showing  characteristic  rosette  of  lanceolate  leaves 
at  the  base  and  portion  of  long  slender  scape  with  numerous  tubular  flowers.  The  plant  is 
common  in  dry  coniferous  woods  in  the  eastern  part  of  the  United  States. 

the  summit.  The  leaves  are  lanceolate,  with  spinose  margins,  and 
furnished  with  stout  terminal  spines.  The  leaves  as  well  as  the 
roots  contain  a  large  amount  of  mucilage  which  retains  water  and 


CLASSIFICATION  OF  ANGIOSPERMS. 


491 


FIG.  272.  Swamp  Pink  (Helonias  bullata)  is  a  rather  rare  plant  found  only  in  certain 
localities,  particularly  in  wet  places,  extending  from  southern  New  York  to  Virginia.  It 
produces  a  tuberous  root-stock,  and  the  evergreen  leaves  are  clustered  near  the  base  of  a 
naked  scape  which  bears  in  the  early  spring  a  short  raceme  of  purplish  flowers.  This 
should  not  be  confounded  with  the  plant  yielding  the  drug  known  as  Helonias  or  false 
unicorn  root,  the  latter  being  derived  from  Chamcelirium  luteum,  and  at  one  time  known 
as  Helonias  dioica. — After  Troth. 


492  A  TEXT-BOOK  OF  BOTANY. 

thus  helps  to  adapt  the  plants  to  these  arid  regions.  The  plants 
grow  slowly  and  may  flower  when  they  are  ten  or  twelve  years  old. 
The  Agaves  contain  saponin  and  other  principles  of  medicinal 
value.  They  yield  a  number  of  other  products,  as  follows : 
PULQUE,  a  fermented  drink  of  the  Mexicans ;  MEZCAL,  a  distilled 
drink  resembling  rum;  various  fibers,  as  SISAL  HEMP,  "  Hene- 
quen  "  or  "  Sacci/'  etc.  Other  members  of  the  Amaryllidacese 
likewise  find  use  as  medicines  and  as  foods,  many  of  them  being 
cultivated  as  ornamental  plants,  as  Narcissus,  Hymenocallis, 
Crinum,  and  Amaryllis. 

c.  DIOSCOREACE.E  OR  YAM  FAMILY.— The  plants  be- 
longing to  this  family  are  twining  shrubs  or  herbs  with  tubers 
either  above  or  below  ground.     The  general  characters  of  the 
plants  are  shown  in  the  wild  yam-root  (Dioscorea  villosa)  of  the 
United  States  (Fig.  180).     Several  species,  notably,  D.  Batatas, 
yield  the  YAMS  or  Chinese  potatoes  of  commerce. 

Many  of  the  species  of  Dioscorea,  as  well  as  other  members  of 
this  family,  contain  active  principles  which,  like  those  of  the 
Aracese  and  Liliacese,  are  destroyed  on  heating.  The  rhizome  of 
Tamus  communis  contains  saponin,  and  Rajania  subamarata  con- 
tains tannin. 

d.  IRIDACE^E  OR  IRIS  FAMILY.— The  plants  of  this  fam- 
ily are  perennial  herbs  with  mostly  equitant   (bilateral)    leaves 
and  horizontal  rhizomes,  or  corms.     The  flowers  are  regular  or 
irregular  and  with  a  petalloid  stigma  (Fig.  254,  B). 

Iris  versicolor  is  a  flag-like  plant,  commonly  known  as  the 
LARGER  BLUE  FLAG,  and  found  abundantly  in  the  marshes  and  wet 
meadows  of  the  Eastern  United  States.  It  is  distinguished  by  its 
tall*  stems  and  sword-shaped,  somewhat  glaucous  leaves.  The 
flowers  are  violet-blue.  The  rhizome  somewhat  resembles  that  of 
calamus,  but  is  of  a  dark  brown  color  and  contains  25  per  cent,  of 
acrid  resins,  a  volatile  oil,  starch,  and  tannin. 

Iris  florentina,  which  yields  the  ORRIS  ROOT  of  commerce  (Fig. 
190),  is  a  plant  cultivated  in  Middle  and  Southern  Europe,  and 
closely  resembles  the  above-mentioned  species.  The  rhizome  con- 
tains a  volatile  oil  resembling  that  found  in  violets,  and  is  used 
in  perfumery.  Orris  root  is  also  obtained  from  Iris  germanica 
and  /.  pallida.  The  violet  odor  is  developed  on  keeping  the  rhizome 
a  vear  or  two. 


CLASSIFICATION  OF  ANGIOSPERMS.  .         493 

Crocus  sativus,  the  orange-red  stigmas  of  which  have  been  used 
in  medicine  since  ancient  times,  is  an  autumnal-flowering  plant. 
The  flowers  are  lilac-purple,  somewhat  like  those  of  Colchicum, 
and  occur  at  the  summit  of  a  scape  rising  15  to  20  cm.  above 
ground.  The  leaves  are  linear  and  rise  directly  from  a  more  or 
less  globular  corm.  The  plant  is  cultivated  in  Spain  and  other 
parts  of  Europe  and  in  the  United  States  as  well.  The  stigmas 
constitute  the  drug  SAFFRON  (Crocus),  which  was  formerly  official, 
and  contain  a  coloring  principle,  I  part  of  which  will  impart  a 
distinct  yellow  color  to  100,000  parts  of  water.  Saffron  contains 
a  yellow  glucoside,  CROCIN,  which  is  soluble  in  alcohol  but  not  in 
water,  and  is  colored  blue  by  sulphuric  acid.  The  drug  also  con- 
tains 7.5  to  10  per  cent,  of  a  volatile  oil,  which  appears  to  be 
derived  from  a  coloring  principle  that  resembles  carotin ;  and  the 
bitter  principle  picro-crocin. 

e.  JUNCACE^  OR  RUSH  FAMILY.— These  are  grass-like 
marsh  plants,  which  are  distinguished  by  the  fact  that  the  flowers 
are  small,  with  a  6-parted  glumaceous  perianth,  and  the  fruit  is  a 
loculicidally  dehiscent  capsule.  The  stems  are  mostly  solid,  slen- 
der, usually  arise  in  tufts  from  the  rhizome,  and  are  characterized 
by  stellate  parenchyma  cells,  among  which  are  large,  intercellular 
spaces,  the  latter  also  being  characteristic  of  the  leaves.  The 
rushes  are  principally  found  in  cold  and  temperate  regions. 

Several  species  of  Juncus  and  Luzula  have  been  used  in  medi- 
cine, particularly  in  Europe.  The  seeds  of  Luzula  compestris, 
a  common  wood  rush  of  the  United  States  naturalized  from 
Europe,  are  edible.  Soft  rush  (Juncus  effusus)  and  Hard  rush 
(/.  conglomerate)  are  used  in  Japan  in  the  manufacture  of  rush 
matting.  In  Holland  the  rush  is  grown  on  the  embankments 
along  the  coast  to  prevent  the  action  of  the  tides. 

VIII.    ORDER  SCITAMINALES  OR  SCITAMINE^E. 

The  plants  of  this  order  are  mostly  found  in  the  Tropics  and 
are  perennial  herbs  with  fleshy  rhizomes.  The  leaves  are  large, 
more  or  less  elliptical  and  pinnately  veined.  The  leaf  sheaths  close 
tightly  around  each  other  and  form  a  kind  of  false  stem.  The 
flowers  are  epigynous,  unsymmetrical  or  zygomorphic,  and  fre- 
quently only  one  stamen  is  completely  developed. 


494  A  TEXT-BOOK  OF  BOTANY. 

a.  THE  ZINGIBERACE;E  OR  GINGER  FAMILY  is  dis- 
tinguished from  the  other  Scitaminese  by  the  fact  that  the  seeds 
have  endosperm  as  well  as  perisperm.  The  plants  are  rich  in 
volatile  oils,  and  a  number  are  used  in  medicine  and  perfumery. 

Zingiber  officinale  yields  the  official  ginger  (Fig.  273).  From 
a  creeping,  fleshy,  branching  and  laterally  compressed  rhizome 
(Fig.  187)  arises  a  stem  about  i  M.  high  bearing  numerous  lanceo- 
late leaves.  The  flowering  stalk  arises  directly  from  the  rhizome, 
terminating  in  a  spike  which  bears  flowers  having  greenish-yellow 
petals  with  violet  or  purple  stripes. 

Elettaria  Cardamomum  (E.  repens)  yields  the  cardamom  of 
the  several  pharmacopoeias  (Fig.  237).  The  plant  has  a  leafy  as 
well  as  floral  stem  which  rises  from  a  tuberous  rhizome.  The 
leaves  are  broadly  lanceolate.  The  flowers  are  greenish-white, 
the  labellum  (consisting  of  two  petal-like  staminodes)  being  bluish. 
The  fruit  is  a  capsule,  and  the  seeds  are  the  part  used  in  medicine. 

The  so-called  PARADISE  GRAINS  are  the  seeds  of  Amomum 
Melegueta  growing  in  Western  Africa.  They  are  about  3  mm.  in 
diameter,  dark  brown,  nearly  smooth,  friable,  and  contain  a  vola- 
tile oil. 

GALANGAL,  which  is  used  in  perfumery,  is  the  rhizome  of 
Alpinia  Galanga  growing  in  the  East  Indies  and  cultivated  in 
China  and  Bengal.  It  is  frequently  referred  to  as  "  Galangal 
major  "  to  distinguish  it  from  the  rhizome  of  Alpinia  officinarum 
growing  in  China  near  Hainan.  Galangal  occurs  in  short,  branched 
pieces  of  a  reddish-brown  color,  with  numerous  circular  scars, 
and  has  an  aromatic  and  pungent  taste.  It  contains  0.5  per  cent, 
of  a  volatile  oil,  the  principal  constituent  of  which  is  cineol ;  a 
pungent  principle,  galangol ;  an  acrid,  pungent  resin ;  25  per  cent, 
of  starch ;  and  three  crystalline  principles. 

CURCUMA  or  TURMERIC  is  the  rhizome  of  Curcuma  longa,  a 
reed-like  plant  which  is  largely  cultivated  in  India  and  other 
tropical  countries.  In  preparing  the  rhizome  for  market  it  is  sub- 
jected to  a  scalding  or  parboiling  process  which  agglutinates  the 
starch  in  the  cells.  While  turmeric  is  used  as  a  condiment,  it  is 
also  used  on  account  of  its  color  as  an  adulterant  of  mustard, 
rhubarb,  and  other  articles,  but  is  very  easily  detected.  Several 
forms  of  curcuma  are  found  in  commerce,  as  "  round  curcuma," 


CLASSIFICATION  OF  ANGIOSPERMS.  495 

consisting  of  the  main  rhizome,  and  "  long  curcuma,"  composed 
of  the  short  branches.    They  occur  in  cylindrical  or  ovoid  pieces, 


FIG.  273.  Zingiber  officinale,  the  rhizome  of  which  constitutes  the  ginger  of  the  market. 
Entire  plant  showing  rhizome  and  roots,  a  leaf-branch  and  a  flower-branch,  as  also  scars  of 
previous  year's  growth  after  decay  of  leaf-  and  flower-branches.  A,  entire  flower;  B,  sec- 
tion of  flower  showing  beak-like  appendage  at  the  apex  of  the  fertile  stamen,  which  encloses 
the  style;  C,  three-parted  labellum  or  irregular  segment  of  corolla  showing  2  tooth- 
like  staminodes  (rudiments  of  stamens)  at  the  base;  D,  the  ovary  with  lower  portion  of 
style  and  two  epigy nous,  filiform  processes  which  secrete  nectar;  E,  apex  of  funnel-shaped, 
fringed  stigma. — After  Berg  and  Schmidt. 

2  to  5  cm.  long,  of  a  yellowish-brown  color  externally,  bright  yel- 
low internally,  and  aromatic  odor  and  taste.     Curcuma  contains 


496  A  TEXT-BOOK  OF  BOTANY. 

i  per  cent,  of  volatile  oil  containing  phellandrene  and  turmerol ;  0.3 
per  cent,  of  a  yellow  crystalline  principle,  CURCUMIN,  which  is 
soluble  in  alcohol,  sparingly  soluble  in  water,  forms  reddish-brown 
solutions  with  alkalies  and  is  converted  into  vanillin  with  weak 
oxidizing  agents.  It  also  contains  considerable  starch  and  a  small 
quantity  of  an  alkaloid. 

Other  families  of  the  Scitamineae  are  of  great  importance  on 
account  of  the  food-products  obtained  from  them,  as  the  Musa- 
cece,  which  contains  the  group  of  plants  to  which  the  BANANA 
(Musa  paradisiaca  and  M.  Sapientum)  belongs.  To  the  Canna- 
cece  belong  the  cultivated  Cannas,  one  of  them,  Canna  edulis, 
being  grown  extensively  in  the  West  Indies  and  Australia  as  a 
vegetable,  and  another,  Canna  coccinea,  which  grows  in  the  West 
Indies  and  South  America,  furnishing  "  Tous  les  mois,"  the 
arrow-root  starch  of  the  English  and  French.  To  the  Maranta- 
ce&  belongs  Maranta  arundinacea,  which  is  cultivated  in  tropical 
America,  and  the  rhizome  of  which  yields  the  starch,  MARANTA 
ARROWROOT  (Fig.  88,  5),  and  is  largely  used  in  the  preparation  of 
infants'  food. 

IX.    ORDER  ORCHIDALES  OR   MICROSPERM^E. 

The  most  important  family  of  this  order  is  the  ORCHIDACE^E  or 
ORCHID  FAMILY.  The  orchids  are  the  most  highly  specialized 
of  the  Monocotyledons.  They  are  perennial  herbs  with  diverse 
habits,  many  tropical  species  being  epiphytes,  and  of  varying  mor- 
phological structure,  which  is  particularly  evident  in  the  zygo- 
morphic  flowers.  The  perianth  consists  of  6  segments.  The  3 
outer  correspond  to  sepals  and  are  similar.  Two  segments  of  the 
inner  circle  correspond  to  petals  and  are  alike,  while  the  third, 
which  is  known  as  the  LIP,  is  remarkably  modified,  being  usually 
larger,  often  spurred,  and  frequently  reversed,  being  turned  for- 
wards and  downwards  by  the  twisting  or  torsion  of  the  ovary. 
Only  one  of  the  stamens — the  anterior  of  the  external  whorl — is 
developed  and  bears  an  anther.  The  other  stamens  are  entirely 
wanting  or  present  as  staminodes  (except  in  Cypripedium  and  the 
Apo-stasieae).  The  filament  is  united  with  the  style  to  form  a 
column,  the  so-called  "  stylar  column,"  and  the  anther  is  thus 
placed  on  its  apex,  and  behind  the  stigma.  The  3  carpels  form  a 
unilocular  ovary  with  3  parietal,  deeply  bifid  placentae.  The  fruit 


CLASSIFICATION  OF  ANGIOSPERMS. 


497 


is  a  pod  or  capsule,  which  dehisces  mostly  by  means  of  6  valves, 
and  contains  numerous  minute  seeds,  which  are  without  endo- 
sperm, and  the  embryo  of  which  lacks  frequently  any  trace  of 
external  organs.  The  seed-coat  is  membranous  and  loose. 


FIG.  274.  A  fruiting  plant  of  Vanilla  planifolia,  an  epiphytic  orchid,  which  is  indige- 
nous to  Mexico  and  extensively  cultivated  in  tropical  countries,  especially  in  Mexico  and 
Java.  The  photograph  is  of  a  plant  growing  in  Dominica,  an  island  of  the  West  Indies, 
and  shows  the  long,  elliptical  leaves,  also  some  of  the  long,  slightly  curved,  slender  pods. 
The  latter  are  not  fragrant,  but  develop  their  characteristic  aroma  by  a  process  of  slow 
curing. — Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

Vanilla  planifolia,  which  yields  the  official  vanilla,  is  a  high- 
climbing  plant  with  long  internodes  and  distinct  nodes  from  which 
arise  more  or  less  oval  or  broadly  lanceolate,  somewhat  fleshy 
leaves  and  also  commonly  a  single  aerial  root.  The  long  stem 
is  terminated  by  a  raceme,  flowers  also  arising  in  the  axils  of  the 
32 


498 


A  TEXT-BOOK  OF  BOTANY, 


FIG.  275.  Moccasin  Flower  or  Pink  Lady's  Slipper  (Cypripedium  acaule),  one  of  the 
commonest  and  most  beautiful  of  the  orchids,  found  growing  in  sandy  and  rocky  woods  from 
Newfoundland  to  North  Carolina,  and  westward  from  Minnesota  to  Kentucky.  The 
crimson  pink  flowers  are  solitary  at  the  summit  of  long  scapes;  the  lip  is  large  inflated, 
slipper-shaped,  drooping  and  with  a  fissure  in  front  instead  of  a  circular  opening  as  in  the 
other  species. — After  Troth. 

leaves  for  some  distance  back  on  the  stem.  The  flowers  are  yel- 
lowish-green and  the  segments  of  the  perianth  are  similar,  and 
erect  or  spreading.  The  lip  is  united  with  the  column,  forming  a 


CLASSIFICATION  OF  ANGIOSPERMS.  499 


FIG.  276.  Round-leaved  Orchis  (Habenaria  orbiculata) ,  an  interesting  orchid  found 
growing  in  rich  deep  woods  in  the  north  temperate  regions  of  the  United  States.  It  has  a 
leafless  scape,  at  the  base  of  which  are  two  orbicular  or  elliptical  leaves  spreading  flat  on  the 
ground.  The  flowers  are  in  a  loose  raceme,  greenish-white,  the  lip  being  oblong  linear  and 
about  the  same  length  as  the  spur. — After  Troth. 


A  TEXT-BOOK 


BOTANY. 


FIG.  277.  White  Fringed  Orchis  (Habenana  blephariglottis),  an  attractive  and  rather 
common  orchid  growing  in  bogs  and  peaty  lands  throughout  the  eastern  and  centra!  United 
States.  The  stems  are  from  4  to  6  dm.  in  length,  terminated  by  many-flowered  spike.  The 
flowers  are  white,  the  lip  being  copiously  fiinged  and  the  spur  about  2  cm.  in  length. — After 
Troth. 

cylindrical  body  which  is  strongly  concave  on  one  side  and  spread- 
ing at  the  upper  portion.     The  pollinia  are  granular.     Pollination 


CLASSIFICATION  OF  ANGIOSPERMS.  501 

may  be  effected  by  insects,  but  is  usually  brought  about  by  arti- 
ficial means  (hand-pollination) .  The  fruits  require  several  months 
to  become  fully  grown,  and  an  equal  period  of  time  is  necessary 
for  their  maturity,  which  is  indicated  by  their  yellow  color.  They 
are  then  gathered  and  cured  by  alternately  steaming  and  drying 
them,  until  they  acquire  the  dark  brown  color  and  the  odor  of  the 
commercial  article.  Vanilla  is  cultivated  in  all  tropical  countries 
where  the  temperature  does  not  fall  below  18°  C,  and  the  humidity 
is  considerable.  Usually  vanilla  culture  is  combined  with  that  of 
Cacao.  The  plants  begin  to  yield  fruits  the  third  year  and  continue 
bearing  for  thirty  or  forty  years  (Fig.  274). 

The  yellow-flowering  Cypripediums  of  the  United  States  (C. 
parviflonnn  and  C.  parvifloruni  pubescent)  yield  the  cypripedium 
which  was  formerly  official.  The  plants  are  a  foot  or  two  high. 
The  leaves  are  oval  or  elliptical  (in  the  latter)  or  elliptical  or 
lanceolate  (C.  parvifloruwi} .  In  C,  pubescens  the  lip  is  pale  yellow 
with  purple  veins,  25  to  50  millimeters  long,  and  possesses  a  tuft  of 
white,  jointed  hairs  at  the  throat.  In  C.  parviflorum  the  lip  is 
smaller  and  non-hairy.  C.  acaule  is  shown  in  Fig.  275. 

The  root-stocks  of  a  number  of  Orchids  are  rich  in  mucilage 
and  yield  the  drug  salep  or  a  product  resembling  it.  Salep  occurs 
in  the  form  of  globular  or  somewhat  flattened,  more  or  less  trans- 
lucent, light  yellowish-brown  tubers,  2  to  4  cm.  long,  of  a  horny 
texture  and  a  mucilaginous  taste.  The  principal  constituent  is 
mucilage,  which  originates  in  the  cell-contents.  It  may  contain 
in  addition  either  starch  or  sugar. 

While  the  Orchidaceae,  which  contains  about  6,000  species, 
ranks  second  in  numbers  to  the  Composite,  there  is  probably  no 
family  which  exceeds  it  in  interest.  The  plants  are  extensively 
cultivated,  and  some  of  their  flowers  are  the  highest  priced  known 
in  the  commercial  world.  There  are  few  localities  in  which  there 
are  not  some  orchids  to  be  found,  illustrations  of  several  of  which 
are  here  shown  (Figs.  275  to  279). 

B.  CLASS  DICOTYLEDONE^:. 

The  following  are  some  of  the  prominent  features  of  the 
Dicotyledons:  (i)  The  leaves  are  reticulately  (open)  veined  and 
usually  with  an  irregular  margin,  being  sometimes  deeply  lobed ; 


502 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  278.  Arethusa  bulbosa,  an  Orchid  growing  in  bogs  from  Newfoundland  to  South 
Carolina,  and  west  to  Minnesota.  It  produces  a  solitary  magenta-crimson  flower  on  a  long, 
slender  scape,  in  the  sheaths  of  which  a  solitary  linear  leaf  arises  and  protrudes  after  the 
flower  opens.  In  the  illustration  are  shown  a  number  of  plants,  some  of  which  show  the 
.small  bulbs  at  the  base. — After  Troth. 


(2)  the  parts  of  the  flower  are  usually  in  circles  of  2  to  5  each; 

(3)  the  stems  and  roots  generally  increase  in  thickness  by  means  of 
a  cambium,  and  the  vascular  bundles  are  open,  varying   from 


CLASSIFICATION  OF  ANGIOSPERMS. 


FIG.  279.  Rattlesnake  Plantain,  a  rather  common  orchid,  variously  known  as  Epi- 
Pactis,  Peramium,  or  Goody  era  pubescens.  It  is  generally  found  growing  in  coniferous  woods 
and  characterized  by  the  dark-green  basal  leaves  with  their  prominent  nerves  and  numerous 
white  reticulating  veins.  The  flowers  are  greenish-white,  numerous  and  crowded  on  the 
erect  scapes. — After  Troth. 

simple  collateral  to  bi-collateral ;  annular  rings  are  formed  in  the 
perennial  stems;  (4)  the  germinating  plant  usually  has  two  coty- 
ledons which  are  opposite  each  other.  The  Dicotyledons  are 
divided  into  two  series  or  sub-classes,  depending  upon  whether 


504  A  TEXT-BOOK  OF  BOTANY. 

the  parts  of  the  corolla  are  distinct  or  are  united,  namely,  the 
Archichlamydeae  and  Metachlamydese. 

ARCHICHLAMYDE^E  OR  CHORIPETAL^. 

The  Archichlamydeae  or  Choripetalse  comprise  those  dicoty- 
ledonous plants  in  which  the  petals  are  separate  and  distinct  from 
one  another  or  are  entirely  wanting. 

I.    ORDER    PIPERALES. 

The  plants  of  this  order  are  mostly  tropical  herbs  and  shrubs 
and  possess  very  small  flowers  which  have  neither  petals  nor  sepals. 
The  leaves  are  simple  and  without  stipules,  the  most  important 
family  medicinally,  as  well  as  in  other  ways,  being  the  PIPERACE/E, 
to  which  the  following  medicinal  plants  belong. 

Piper  nigrum  is  a  woody  climber  that  has  leathery,  grayish- 
green,  ovate-elliptical  leaves  (Figs.  281,  282),  with  three  prominent 
middle  nerves  and  two  side  nerves;  the  flowers  are  perfect, 
sessile  and  form  an  elongated  fleshy  spike ;  the  fruit  is  a  berry 
which  is  yellowish-red  when  ripe.  The  unripe  fruit  constitutes 
the  BLACK  PEPPER  of  commerce.  WHITE  PEPPER  is  the  ripe  berry 
of  Piper  nigrum  from  which  the  epicarp  is  removed,  while  "  LONG 
PEPPER  "  is  obtained  from  Piper  longum,  an  entirely  different 
plant,  and  consists  of  the  entire  spikes  with  immature  fruits. 

Piper  Cubeba  is  a  climbing  perennial,  with  leathery  elliptical- 
ovate  or  long  elliptical  leaves ;  the  flowers  are  dioecious  and 
arranged  in  spikes ;  the  fruit  is  a  berry,  the  pedicel  becoming  much 
elongated  after  fertilization.  The  unripe  fruit  is  the  part  used  in 
medicine  and  is  official  as  cubeb. 

Piper  angustifolium  yields  MATICO,  formerly  official.  The 
plant  is  a  shrub  growing  in  Central  and  South  America  and  is 
characterized  by  its  long,  oblong-lanceolate,  deeply  reticulate,  very 
hairy  leaves.  The  flowers  and  fruits  are  very  small  and  arranged 
in  long,  slender  spikes,  which  are  frequently  found  in  the  drug. 
Matico  contains  2  to  3  per  cent,  of  a  volatile  oil,  containing  a 
stearoptene  matico  camphor,  which  appears  to  be  the  most  im- 
portant constituent.  It  also  contains  an  acrid  resin,  a  bitter  prin- 
ciple, and  a  crystalline  principle,  artanthic  acid.  Other  related 


CLASSIFICATION  OF  ANGIOSPERMS. 


505 


- 

•— «•     \s?e*>ty& — I.---*    v^=-^. 


FIG.  280.  Diagrams  of  cross  sections  of  the  flowers  of  a  number  of  families  of  dicoty- 
ledonous plants  showing  the  number  and  position  of  the  parts  with  reference  to  each  other: 
t,  stem  of  plant;  f,  foliage  leaf;  b,  bracts  or  leaves  on  the  flower-stalk;  s,  sepals;  p,  petals; 
a,  stamens;  c,  ovary;  per,  perianth.  A,  Linaceae;  B,  Cruciferae;  C,  genus  Citrus;  D, 
Rosaceae;  E,  Berberidaceae,  showing  nectaries  (k)  on  the  petals;  F,  Lauraceae,  showing 
staminodes  (g);  G,  epigynous  flower  of  Rubiaceae;  H,  Ericaceae;  I,  Labiatae,  showing 
position  of  other  flowers  (sv)  in  the  cymes;  J,  Violaceae  showing  spurred  stamens;  K, 
Campanulaceae,  showing  bracts  (a,  /3)  the  relation  of  the  sepals  (1,2,3,4  and  5),  and  two  pos- 
terior hairy  stamens;  L,  Leguminosae,  showing  the  large  posterior  petal  (p)  known  as  the 
vexillum  or  standard,  the  two  lateral  petals  (v)  situated  under  the  standard  known  as  alse 
or  wings,  and  the  two  anterior  petals  which  are  covered  by  the  wings  and  part.ly  cohering 
to  form  a  prow-shaped  body  called  the  carina  or  keel  (k). — Adapted  from  Warming. 


506 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  281.  Black  pepper  (Piper  nigrum),  a  climbing  shrub  growing  in  Botanic  Gardens, 
Port  of  Spain,  Trinidad.  The  illustration  shows  the  ovate-elliptical  leaves,  opposite  which 
are  the  fruiting  spikes,  which  when  ripe  are  of  a  yellowish-red  color.  The  plant  has  been 
introduced  into  many  tropical  countries  and  is  not  infrequently  seen  in  botanic  gardens 
throughout  the  civilized  world. — Reproduced  by  permission  of  The  Philadelphia  Commercial 
Museum. 

species  of  Piper  are  used  in  tropical  America  similarly  to  Piper 
angnstifolium. 

The  leaves  of  a  number  of  species  of  Piper  (known  as  "  betel 


CLASSIFICATION  OF  ANGIOSPERMS.  507 


5o8  A  TEXT-BOOK  OF  BOTANY. 

leaves  ")  are  mixed  with  the  Areca  nut  and  lime  and  constitute 
what  is  known  as  "  BETEL,"  which  compound  is  used  for  chewing, 
in  India  and  other  countries,  chiefly  on  account  of  its  astringency. 
The  root  of  Piper  methysticum  is  also  chewed,  and  when  mixed 
with  the  milk  of  the  Cocoanut  yields  an  intoxicating  drink  which 
is  used  by  the  inhabitants  of  the  Sandwich  Islands.  The  dried 
root  has  been  used  in  medicine  under  the  name  of  METHYSTICUM 
or  KAVA-KAVA.  It  consists  of  large,  branching,  soft,  spongy, 
dark  brown  pieces,  which  are  tough,  fibrous,  and  with  a  pungent, 
somewhat  bitter  taste.  Kava-kava  contains  3  resins,  one  of  which 
has  marked  anaesthetic  properties ;  an  alkaloid,  kavaine ;  a  neutral 
body,  methysticin ;  and  about  50  per  cent,  of  starch.  The  drug  is 
free  from  calcium  oxalate  crystals,  these  being  usually  wanting 
in  the  Piperacese. 

•y>f  ";"' 

II.    ORDER   SALICALES. 

This  order  comprises  but  a  single  family,  namely,  the  SALI- 
CACEJE  or  Willow  Family,  to  which  belong  the  willows  and  pop- 
lars. The  plants  are  dioecious  shrubs  and  trees ;  the  flowers  being 
in  aments  or  catkins  and  without  petals  or  sepals.  The  fruit  is  a 
capsule  containing  many  seeds  which  are  small  and  with  long,  silky 
hairs  at  the  base. 

The  barks  of  a  number  of  the  members  of  this  group  contain 
glucosides,  as  salicin,  which  is  found  in  Salix  alba,  the  white  willow 
of  Europe  and  the  United  States,  and  the  brittle  willow  Salix  fra- 
gilis;  and  populin,  which  is  found  in  the  white  or  silver-leaf  poplar 
(Populus  alba)  of  Europe,  Asia,  and  the  United  States  and 
Populus  pyramidalis  of  Italy.  These  principles  are  also  found  in 
other  species  of  willow  and  poplar.  A  number  of  the  barks  con- 
tain a  yellow  coloring  principle  allied  to  quercitrin,  as  Salix  daph- 
noides  of  Europe  and  Salix  alba.  Tannin  is  a  common  constituent 
in  both  the  willows  and  poplars.  The  buds  of  many  of  the  poplars 
contain  in  addition  a  volatile  oil  which  is  in  the  nature  of  a  di- 
terpene,  as  those  of  Populus  pyramidalis.  Populus  balsamifera, 
the  tacamahac  or  balsam  poplar  of  the  United  States  and  Canada, 
furnishes  the  BALM  OF  GILEAD  buds  which  are  coated  with  an 
oleo-resin  that  gives  them  their  aromatic  properties.  Populus 


CLASSIFICATION  OF  ANGIOSPERMS.  509 

nigra  yields  a  volatile  oil,  of  which  the  important  constituent  is 
humulene. 

The  charcoal  used  medicinally  is  prepared  by  burning  the  wood 
of  the  young  shoots  of  the  white  and  black  willow,  poplar,  beech, 
or  linden  without  access  of  air. 

III.    ORDER  MYRICALES. 

This  group  somewhat  resembles  the  Salicales  in  that  the  flowers 
are  in  aments.  The  flowers  are  either  pistillate  or  staminate, 
and  mostly  dioecious  in  our  native  species.  The  most  important 
family  is  the  MYRICACE^E  or  Bayberry  Family.  The  genus  Myrica 
is  especially  characterized  by  the  fact  that  the  outer  layer  of  the 
drupe  is  waxy.  This  is  particularly  true  of  the  following  species : 
Myrica  cerifera,  the  wax  myrtle  of  the  sandy  swamps  of  the  United 
States,  contains  a  volatile  oil.  The  fruit  of  sweet  gale  (M.  Gale) 
yields  a  volatile  oil  containing  a  camphor.  The  sweet  fern  (  Comp^ 
tonia  peregrina)  found  in  the  United  States  yields  a  volatile  oil 
resembling  that  of  cinnamon.  The  rhizome  of  this  plant  contains 
also  tannin  and  possibly  gallic  and  benzoic  acids. 

IV.    ORDER   JUGLANDALES. 

The  plants  are  trees  with  alternate,  pinnately-compound  leaves. 
The  staminate  flowers  are  in  drooping  aments,  the  pistillate  being 
solitary  or  several  together.  The  flowers  are  monoecious  and 
have  a  more  or  less  distinct  perianth  consisting  of  3  to  6  lobes. 
The  fruit  is  a  kind  of  drupe  formed  by  the  union  of  the  torus 
with  the  wall  of  the  ovary.  There  is  but  one  family  in  this  order, 
namely,  the  JUGLANDACE^E  (Walnut  family),  which  includes  the 
hickory  (Hicoria)  and  walnut.  The  black  walnut  (Juglans 
nigra)  of  the  United  States  yields  a  valuable  timber  and  an  edible 
nut;  the  white  walnut  or  butternut  (/.  cinerea)  of  the  United 
States  yields  the  butternuts  which  are  edible,  and  a  bark  which  has 
medicinal  properties  and  was  formerly  official  under  the  name  of 
JUGLANS.  It  contains  about  7  per  cent,  of  a  yellow,  crystalline 
acrid  principle  which  is  colored  purple  with  alkalies ;  2  to  2.5  per 
cent,  of  a  crystalline  resin;  volatile  oil,  tannin,  sugar,  and  a 
fixed  oil.  The  bark  of  the  stems  of  the  butternut  tree  is  used  in 
dyeing.  The  ripe  fruits  are  edible,  as  also*  the  green  nuts  when 


510  A  TEXT-BOOK  OF  BOTANY. 

pickled.  The  sap  of  the  tree  contains  a  sugar.  The  wood,  though 
inferior  to  black  walnut,  is  used  in  cabinet  making. 

/.  regia,  native  of  Persia  and  cultivated  in  various  parts  of 
Europe  and  California,  yields  the  edible  ENGLISH  WALNUT. 

The  following  species  of  hickory  yield  edible  nuts :  The  shell- 
bark  hickory  (Hicoria  ovata)  ;  the  pecan  (H.  pecan)  common 
from  Illinois  southward;  and  western  shell-bark  hickory  (H. 
sulcata).  The  wood  of  these  as  well  as  H.  glabra  and  other  species 
of  hickory  is  used  where  strength  and  elasticity  are  required. 

Coloring  principles  are  found  in  the  barks  of  a  number  of 
species  and  are  used  for  technical  purposes.  The  following  con- 
tain yellow  coloring  principles :  Hicoria  ovata,  H.  sulcata,  and 
H.  glabra  (pig-nut  hickory)  ;  green  coloring  principles  are  found 
in  H.  tomentosa,  and  yellowish-brown  principles  in  Juglans  nigra, 
J.  cinerea,  and  /.  regia. 

The  fatty  oils  from  the  cotyledons  (kernels)  of  both  hickory- 
nuts  and  walnuts  are  articles  of  commerce,  and  they  have  been 
used  in  medicine. 

V.    ORDER   FAGALES. 

The  plants  are  trees  or  shrubs  with  alternate,  petiolate,  simple, 
pinnately  veined  leaves.  The  flowers  are  in  aments,  monoecious, 
and  with  a  more  or  less  distinct  perianth.  The  fruit  is  a  nut  which 
is  subtended  by  the  mature  involucre  (bur  or  cup)  or  samara, 
the  seeds  being  without  endosperm  (Fig.  283). 

a.  BETULACE^  OR  BIRCH  FAMILY.— The  plants  are 
aromatic  trees  or  shrubs  and  are  represented  in  the  United  States 
by  such  trees  as  hornbeam  (Carpinus),  ironwood  (Ostrya),  and 
birch  (Betula)  ;  and  by  such  shrubs  as  the  hazelnut  (Corylus)  and 
alder  (Alnus).  The  plants  yield  a  volatile  oil  consisting  largely 
of  methyl  salicylate.  The  bark  of  the  sweet  birch  {Betula  lenta) 
yields  the  oil  of  betula  which  is  official  and  closely  resembles  the 
oil  of  wintergreen.  The  bark  of  a  number  of  plants  of  this  family 
yields  tannin  and  yellow  coloring  principles.  A  number  of  species 
of  Betula  yield  a  sweet  sap,  as  B.  lenta,  and  B.  Bhojpattra  of  Rus- 
sia. The  nuts  of  some  species  are  edible,  as  the  filbert  or  hazelnut 
of  Europe  (Corylus  Avellana),  the  hazelnut  of  the  Orient  (C. 
Colurna),  the  American  hazelnut  (C.  americana). 


CLASSIFICATION  OF  ANGIOSPERMS.  511 

b.  FAGACE^  OR  BEECH  FAMILY.— This  family  includes 
some  of  our  largest  forest  trees,  these  being  rather  characteristic 
of  temperate  regions.  They  are  all  highly  valued  for  their  timber, 
and  yield  other  valuable  products  besides.  One  notable  character- 
istic is  that  all  of  the  chestnuts  and  oaks  and  some  of  the  beeches 


FIG.  283.  White  oak  (Quercus  alba):  A,  characteristic,  lobed  leaf;  B,  young  branch 
showing  pistillate  (p)  and  staminate  (s)  flowers;  C.  hairy  bracts  of  a  staminate  flower;  D, 
group  of  hairs  from  bract;  E,  stamen;  F.  pollen  grains;  G,  cluster  of  pistillate  flowers;  H, 
acorn  with  cupule;  I,  starch  grains  from  acorn,  which  vary  from  10  to  25  M  long;  J.  trans- 
verse section  of  bark  showing  cork  (k).  stone  cells  (st),  bast  fibers  (b),  crystal  fibers  (ca), 
medullary  rays  (m),  parenchyma  (p) ;  K,  longitudinal  section  of  bark  showing  end  of  bast 
fiber  (b)  crystal  fibers  (ca)  and  parenchyma  cells  (t)  containing  tannin. 

contain  tannin  in  the  wood,  bark,  and  leaves.  The  oaks  are  further 
notable  in  being  prone  to  the  attack  of  gall-producing  insects 
(various  species  of  Cynips)  whereby  the  peculiar  excrescences 
known  as  galls  are  formed  on  the  leaves  and  young  shoots.  Among 
the  oaks  which  yield  galls  rich  in  tannin  are  the  following :  Quercus 
infectoria  of  the  Mediterranean,  which  yields  the  official  Turkish 


512  A  TEXT-BOOK  OF  BOTANY. 

or  Aleppo  galls  (pp.  206,  334)  ;  Quercus  Robur,  which  is  some- 
times divided  into  Q.  pubescens  and  Q.  pedunculata,  yields 
a  European  gall;  the  live  oak  (Q.  virginiana)  of  Texas;  and 
Q.  lobata  of  California.  Various  oaks  of  the  Southern  States  also 
produce  "ink  balls  "  or  "  ink  galls,"  as  Q.  cocclnea  and  Q.  imbri- 
caria.  Several  species  of  oak  are  used  in  the  tanning  industry, 
as  that  of  white  oak  (Quercus  alba},  red  oak  (Q.  rubra),  Spanish 
oak  (Q.  digitata),  and  black  oak  (Q.  velutina),  all  of  North 
America;  Q.  pedunculata  and  sessiliflora  of  Germany,  and  Q.  den- 
tata  of  Japan. 

The  glucosidal  coloring  principle  quercitrin  is  found  in  the 
bark  of  Quercitron  or  black  oak  (Q.  velutina}.  Q.  coccifera  of 
Southern  Europe  yields  a  red  coloring  principle  which  is  used  in 
dyeing. 

The  wood  of  the  American  beech  (Fagus  americana)  and  of 
the  European  red  beech  (F.  sylvatica)  yields  a  tar  from  which 
on  distillation  the  official  CREOSOTE  is  obtained. 

The  cork  of  commerce  which  is  used  for  a  variety. of  purposes 
is  derived  from  the  bark  of  several  species  of  Quercus,  namely, 
Q.  Suber  and  Q.  occidentals,  growing  in  Spain,  Southern  France, 
and  Algiers. 

The  cotyledons  of  the  seeds  of  the  Beech  family  are  rich  in 
proteins,  starch,  and  oil,  and  some  of  the  nuts  are  edible,  as  the 
Spanish  CHESTNUTS  obtained  from  Castanea  vulgaris,  American 
chestnut  from  C.  dentata,  and  CHINQUAPIN  from  C.  puniila  (Fig. 
202).  . 

VI.    ORDER  URTICALES. 

This  order  embraces  three  families  which,  while  they  agree  in 
certain  characters,  are  quite  distinct  in  other  ways. 

a.  ULMACE^  OR  ELM  FAMILY.— The  plants  are  trees 
or  shrubs  with  alternate,  simple,  serrate,  petiolate  leaves.  The 
flowers  are  monoecious  or  dioecious,  with  a  4-  to  6-divided  peri- 
anth. The  fruit  is  a  i-seeded  drupe,  samara,  or  nut.  The  typical 
group  of  this  family  is  that  of  the  elms,  of  which  the  American 
or  white  elm  (Ulmus  americana)  is  the  most  prized  for  orna- 
mental purposes.  The  elms  yield  valuable  timber,  and  the  bark  of 
Ulmus  campestris  of  Europe  is  used  for  tanning  and  dyeing  be- 
cause of  the  presence  of  tannin  and  a  yellow  coloring  principle. 


CLASSIFICATION  OF  ANGIOSPERMS. 


513 


The  inner  bark  of  the  red  or  slippery  elm  (Ulmus  fulva)  is 
used  in  medicine  on  account  of  its  mucilaginous  character  (see 
Fig.  119,  C).  The  tree  has  a  gray,  fragrant  bark;  leaves  which 
are  very  rough  above  and  become  fragrant  on  drying,  and  the 
wood  is  reddish-brown.  The  samara  is  not  hairy  as  in  some  of 
the  other  species. 


FIG.  284.  View  taken  in  Ceylon  of  a  part  of  a  grove  of  4-year-old  rubber  trees  (Ficus 
elastica).  This  tree  is  extensively  cultivated  in  Ceylon  and  other  portions  of  tropical  Asia, 
and  most  all  of  the  Asiatic  rubber  is  produced  by  this  tree.  The  trees  may  be  tapped  when 
25  years  old,  and  for  50  succeeding  years  yield  40  pounds  caoutchouc  every  3  years. — 
Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

b.  HORACES  OR  MULBERRY  FAMILY.— The  mem- 
bers of  this  family  are  herbs,  shrubs,  or  trees,  many  of  them  con- 
taining a  milk-juice  or  latex.  There  are  many  representatives  in 
the  tropical  regions  and  some  in  temperate  regions.  The  flowers 
are  unisexual,  with  a  4-  to  5-parted  perianth,  and  occur  in  spikes 
or  ament-like  clusters. 

Cannabis  sativa. — This  is  the  plant  yielding  hemp  and  also  the 
33 


514 


A  TEXT-BOOK  OF  BOTANY. 


drug  Cannabis  indica.  The  plant  is  an  annual  branching  herb 
from  i  to  3  M.  high.  The  leaves  are  alternate  above,  opposite 
below,  digitate  with  5  to  1 1  linear-lanceolate,  deeply  serrate  lobes. 
The  flowers  are  dioecious,  the  staminate  occurring  in  panicles  and 
the  pistillate  in  erect  simple  spikes  (Figs.  409,  410,  412).  From 
the  inner  bark  of  the  stem,  which  is  fibrous,  the  HEMP  FIBER  is 
prepared. 


FIG.  285.  Several  large  rubber  trees  (Ficus  elastica)  growing  in  Java  and  showing 
the  production  of  numerous  aerial  roots  from  the  branches.  It  occurs  in  damp  forests 
from  the  base  of  the  Sikkim  Himalaya  eastward  to  Assam  and  Arracan.  There  are  large 
government  plantations  in  Assam,  and  it  is  also  being  cultivated  in  other  provinces.  Kurz 
remarks  that  it  is  frequent  in  Upper  Burma,  and  that  whole  forests  of  the  species  are  said 
to  exist  in  the  valley  of  Hookhoom. — Reproduced  by  permission  of  The  Philadelphia  Com- 
mercial Museum. 

Humulus  Lupulus  or  hop  is  a  twining  perennial  plant,  curving 
to  the  right,  with  opposite,  palmately  3-  to  7-lobed  (or  simply 
dentate  above)  rough  leaves  (Fig.  286).  The  flowers  are  dioecious, 
the  staminate  ones  occurring  in  panicles  and  the  pistillate  in 
ament-like  spikes.  On  the  inner  surface  of  each  scale  of  the 
ament  occur  two  flowers  consisting  of  a  membranous  perianth 


CLASSIFICATION  OF  ANGIOSPERMS. 


515 


and  a  bicarpellary  ovary  with  two  long  styles.  After  fertilization 
the  aments  become  cone-like,  and  this  compound  fruit  constitutes 
the  hop  of  commerce.  This  fruit  differs  essentially  from  the 
true  strobiles  or  cones  of  the  Gymnosperms  in  that  the  seed  in 
the  latter  is  replaced  by  an  akene.  "  Hops  "  are  extensively  used 


FIG.  286.  Hop  vine  (Humulus  Lupulus):  A,  portion  of  branch  with  pistillate  flowers 
(f)  and  cone-like  fruit  (s) ;  B,  portion  of  rachis  of  strobile  with  two  scales  enclosing  akenes; 
C,  pistil;  D,  hair  from  rachis;  E,  epidermis  of  scale;  F,  longitudinal  section  of  akene  show- 
ing coiled  embryo;  G,  surface  view  of  bract  showing  epidermis  and  cells  containing  calcium 
oxalate;  H,  cystolith  of  leaf;  I,  cystolith  of  stem;  J,  glandular  hairs  (lupulin). 

in  the  manufacture  of  various  beers  and  to  a  limited  extent  in 
medicine. 

Ficus  Carica,  which  yields  the  edible  fig,  is  a  deciduous  tree 
from  3  to  7  M.  high,  and  with  large,  5-lobed,  petiolate  leaves. 
The  flowers  are  situated  in  a  hollow  torus  the  walls  of  which 


Si6  A  TEXT-BOOK  OF  BOTANY. 

after  fertilization  become  thick  and  fleshy,  constituting  the  fruit. 
The  best  figs  come  from  Turkey,  Italy,  Spain,  and  Provence. 

A  large  number  of  the  plants  belonging  to  the  Moraceae  yield 
economic  products,  some  of  which,  as  the  drug  Cannabis  indica 
obtained  from  Cannabis  sativa,  are  powerful  narcotics.  HASH- 
ISH or  BHANG  is  a  preparation  made  from  the  dried  leaves,  stems, 
and  flowers  of  the  pistillate  plants  and  is  smoked  either  alone  or 
with  tobacco,  or  chewed  in  combination  with  other  substances,  or 
an  intoxicating  drink  is  made  from  it,  it  being  extensively  used 
by  the  inhabitants  of  Arabia,  Persia,  India,  and  other  Oriental 
countries.  The  leaves  of  Ficus  Ribes  of  the  Philippine  and  Mo- 
lucca Islands  are  smoked  like  opium.  The  milk- juice  of  a  number 
of  plants  belonging  to  the  Moracese  is  the  source  of  arrow  poisons. 
The  URARI  POISON  of  Brazil  is  obtained  from  Ficus  atrox  ;  the 
IPOH  ARROW  POISON  of  Java  and  Borneo  is  derived  from  the  Upas- 
tree,  Antiaris  toxicara.  Many  of  the  plants  of  the  group  contain 
emetic  principles,  as  the  COCILLANA  BARK  of  Guarea  Rusbyi,  a 
tree  of  Bolivia. 

The  milk- juice  of  quite  a  number  of  species  of  Ficus  yields 
India-rubber  or  caoutchouc  (Fig.  128) ,  as  Ficus  elastica  of  the  East 
Indies,  F.  toxicaria  of  South  America,  F.  clliptica  and  'F.  prinoides 
of  New  Granada  and  several  other  species  of  Brazil,  Brosimum 
spurium  of  Jamaica,  Cecropia  peltata  of  the  West  Indies  and 
South  America,  and  Castilloa  elastica  of  Mexico  and  the  West 
Indies.  Ficus  benghalensis  of  India  and  tropical  Africa,  and 
Ficus  Tsiela  of  India,  yield  gum-lac.  Ficus  altissima  and  F. 
religiose  of  tropical  Asia  yield  shellac  on  the  puncture  of  the  stems 
by  a  hemipterous  insect  (Coccus  lacca). 

A  yellow  coloring  principle  is  found  in  Cudrania  javanensis 
of  tropical  Asia  and  Africa,  Chlorophora  tinctoria  of  Mexico, 
Madura  aurantiaca  (Toxylon  pomiferum)  or  osage  orange,  a 
hedge  plant  of  North  America;  Ficus  tinctoria  of  the  Friendly 
Islands  and  F.  asperrima  of  India.  A  fixed  oil  is  obtained  from 
Artocarpus  Blumei  of  Java. 

A  large  number  of  the  plants  of  the  Moracese  yield  edible 
fruits  besides  the  fig  tree  already  described,  as  the  BREAD-FRUIT 
trees  (Artocarpus  incisa)  of  the  Sunda  Islands  and  the  JACK-TREE 


CLASSIFICATION  OF  ANGIOSPERMS.  517 

(A.  integri folia)  of  the  East  Indies,  the  WHITE  MULBERRY  (Morus 
alba)  and  the  BLACK  MULBERRY  (Morus  nigra). 

The  leaves  of  the  white  mulberry  (Morus  alba),  indigenous, 
to  China  and  cultivated  since  the  twelfth  century  in  Europe  and 
now  in  cultivation  to  a  limited  extent  in  the  United  States,  are 
the  chief  food  of  the  silkworm. 

c.  FAMILY  URTICACE^E.— The  plants  belonging  to  the 
Urticacese  or  Nettle  family  are  chiefly  herbs  with  mostly  petiolate, 
stipulate,  simple  leaves.  The  flowers  are  small  and  with  2  to  5 
distinct  or  more  or  less  united  sepals.  The  fruit  is  an  achene ; 
the  embryo  is  straight  and  surrounded  by  an  oily  endosperm.  The 
stems  and  leaves  of  several  of  the  genera  are  characterized  by 
stinging  hairs,  this  being  especially  true  of  the  sub-group  to  which 
the  genus  Urtica  or  stinging  nettle  belongs.  Of  the  stinging 
nettles  the  following  are  used  in  medicine :  Urtica  dioica  of 
Europe  and  naturalized  in  the  United  States,  U.  spatulata  of 
Timor,  Laportea  crenulata  of  tropical  Asia,  L.  moroides  of 
Queensland,  and  Girardinia  palmata  of  India.  In  the  small 
nettle  (Urtica  urens)  of  Europe  and  the  United  States  an  alka- 
loid has  been  found,  and  Laportea  stimulans  has  been  used  as  a 
fish  poison.  Boehmeria  cor  data  of  Brazil  is  used  as  a  substitute 
for  Arnica.  The  fibers  of  a  number  of  the  Urticacese  have  been 
found  useful,  of  which  the  following  may  be  mentioned :  Urtica 
cannabina  of  Asia,  U.  dioica,  U.  urens  and  Boehmeria  nivea  of 
the  Sunda  Islands  and  China,  the  latter  of  which  yields  RAMIE. 
The  akene  of  Debregeasia  edulis  of  Japan  and  the  rhizome  of 
Pouzolzia  tuberosa  of  China  and  Japan  are  edible. 

VII.    ORDER  PROTEALES. 

The  members  of  this  group  are  mostly  shrubs  and  found  prin- 
cipally in  the  Tropics  and  southern  hemisphere,  several  species 
being  cultivated  in  greenhouses  for  the  sake  of  the  beautifully 
colored  flowers  which  are  in  crowded  inflorescences.  The  order 
is  represented  by  but  a  single  family,  namely,  the  Proteacese. 
The  leaves  are  leathery  and  vary  even  on  the  same  plant  from  sim- 
ple to  compound.  The  glucoside  proteacin  and  a  bitter  principle 
are  found  in  Leucadendron  argenteum  and  L.  continuum,  both 


518  A  TEXT-BOOK  OF  BOTANY. 

of  Africa.  A  gum-resin  is  found  in  Grevillea  robusta  of  Aus- 
tralia, and  a  tannin  in  the  bark  of  Lomatia  obliqua  of  Chile. 

A  golden-yellow  coloring  principle  is  obtained  from  the  flowers 
of  Persoonia  saccata  of  Australia.  The  wood  of  Protea  grandi- 
flora  of  Abyssinia  is  used  in  wagon  building,  and  Leucospermum 
conocarpum  of  Cape  Colony  yields  a  valuable  red  wood  and  a 
tan  bark. 

Banskia  (cmula  of  Australia  and  the  sugar-bush  (Protea  melli- 
fera)  of  Australia  and  P.  speciosa  have  a  sugary  cell-sap.  The 
oily  seeds  of  the  Chilean  hazelnut  (Guevina  Avellana)  are  highly 
prized  as  food  by  the  inhabitants.  The  seeds  of  Brabeium  stellati- 
folium  or  wild  chestnut  of  Cape  Colony  are  poisonous  when  fresh, 
but  on  roasting  they  become  edible  and  are  used  as  a  substitute 
for  coffee. 

VIII.    ORDER    SANTALALES. 

This  order  embraces  a  number  of  families  which  are  quite 
distinct  in  several  respects. 

a.  LORANTHACE^E  OR  MISTLETOE  FAMILY.— The 
plants  are  half-parasites  with  well-developed  leaves  containing 
chloroplastids.     They  live  on  trees  by  means  of  haustoria.     To 
this  family  belongs  the  American  mistletoe   (Phoradendron  fla- 
vescem),  parasitic  on  oaks,  elms,  the  tupelo  (Nyssa),  red  maple 
and  other  deciduous  trees.     The  white,  globose  berries  of  this 
plant  are  quite  poisonous,  as  are  also  those  of  the  European  mistle- 
toe (Viscum  album)  and  the  oak  mistletoe  of  Southern  Europe 
(Loranthus  europccus).     Viscum  album  contains  a  volatile  alka- 
loid, VISCINE,  a  glucoside  and  a  resinous  principle.     This  sub- 
stance serves  to  attach  the  seeds  to  the  barks  of  trees,  where  they 
germinate,  and  it  is  used  in  the  manufacture  of  BIRD-LIME,  which 
owing  to  its  viscid  character  is  used  to  catch  small  birds. 

b.  SANTALACE^E     OR     SANDALWOOD     FAMILY.— 
The  plants  are  chlorophyllous  herbs  or  shrubs  which  are  common 
in  warm  countries,  and  many  of  which  are  parasitic  on  the  roots  of 
other  plants.    A  number  of  them  contain  volatile  oils,  as  the  wood 
of  various  species  of  Santalum.  The  official  oil  of  sandal  is  obtained 
from  the  scented  wood  of  the  white  sandalwood  (Santalum  album), 
a  small  tree  growing  wild  and  also  cultivated  in  India  and  the 


CLASSIFICATION  OF  ANGIOSPERMS.  519 

East  Indian  Archipelago.  The  wood  from  the  East  Indies  is 
known  as  Macassar  sandalwood  and  yields  1.6  to  3  per  cent,  of 
oil,  while  the  Indian  wood  yields  3  to  5  per  cent.  The  oil  consists 
of  90  to  98  per  cent,  of  santalol.  Fiji  oil  of  santal  is  obtained  from 
S.  Yasi;  and  Australian  oil  of  santal  from  Fusanus  acuminatus 
and  F.  spicatus.  The  Chinese  oil  is  obtained  from  Santalum 
Freycinctianum  and  .9.  Preisci. 

c.  FAMILY  BALANOPHORACE.E.— The  plants  of  this 
group  are  indigenous  to  tropical  and  sub-tropical  regions.  They 
are  root-parasites  and  develop  tuberous  rhizomes  and  fleshy  shoots 
which  are  yellow  and  without  foliage  leaves.  Balanophom  elon- 
gata  of  Java  grows  on  the  roots  of  Ficus  and  other  plants,  and 
contains  a  large  quantity  of  wax  and  resin.  Sarcophyte  sanguined 
of  Cape  Colony,  which  lives  on  the  roots  of  certain  Acacias,  con- 
tains a  principle  with  the  odor  o.f  scatol.  Cynomorium  coccineum, 
found  in  the  countries  bordering  the  Mediterranean,  has  a  blood- 
red,  astringent  sap.  The  torus  of  the  flower  of  Langsdorffia  hypo- 
gcca  of  tropical  America  is  edible.  The  plant  is  also  rich  in  wax, 
and  in  New  Granada  it  is  sold  under  the  name  of  "  Siejas  "  and 
burnt  like  a  candle. 

IX.    ORDER   ARISTOLOCHIALES. 

This  order  includes  two  families  which  are  very  different  in 
their  general  habits,  a.  The  Ramesiaceae  are  parasitic  herbs  that 
are  almost  devoid  of  chlorophyll.  The  reddish  vegetative  parts 
penetrate  into  the  tissues  of  the  host,  and  from  these  arise  almost 
mushroom-like  flowers  which  in  the  case  of  Rafflesia  Arnoldii 
of  Sumatra  are  I  M.  in  diameter,  being  probably  the  largest  flowers 
known.  The  plants  of  this  family  are  rich  in  astringent  substances. 

b.  ARISTOLOCHIACE^  OR  BIRTHWORT  FAMILY. 
— The  plants  are  non-parasitic  herbs  or  shrubs,  some  of  which  are 
twining.  The  leaves  are  simple  and  in  many  of  the  plants  more 
or  less  cordate  and  reniform.  The  flowers  are  perfect  and  the 
perianth  is  3-  to  6-lobed.  While  the  flowers  of  our  native  species 
are  rather  small  and  insignificant,  those  of  the  tropical  plants  are 
extremely  curious,  being  generally  of  some  striking  color  and 
of  various  odd  forms. 

Aristolochia  reticulata  is  one  of  the  plants  that  furnishes  the 


520  A  TEXT-BOOK  OF  BOTANY. 

official  drug  serpentaria  (see  Vol.  II).  From  a  slender  rhizome 
with  numerous  hair-like  roots  arise  one  or  more  short,  leafy 
branches  which  are  more  or  less  simple,  somewhat  hairy,  and  bear 
oblong-cordate,  prominent-reticulate,  hairy  leaves  (Fig.  287).  The 
flowers  are  borne  on  slender,  scaly,  basal  branches ;  the  calyx  tube 
is  purplish  and  curved  like  the  letter  "  s,"  being  enlarged  around 
the  ovary  and  at  its  throat.  The  fruit  is  a  capsule  containing 
numerous  flat  or  concave  seeds.  An  allied  species,  Aristolochia 
Serpentaria,  furnishes  the  drug  Virginia  snakeroot.  It  is  a  more 
delicate  plant,  the  leaves  being  ovate-lanceolate,  acuminate;  the 
flowers  are  solitary,  and  in  some  cases  cleistogamous.  This  species 
is  found  growing  in  the  United  States,  more  especially  east 
of  the  Mississippi,  while  Aristolochia  reticulata  is  found  west 
of  the  Mississippi  from  Arkansas  to  Texas.  The  plants  of  this 
genus  contain  volatile  oils,  and  in  addition  to  the  two  species 
mentioned  45  other  species  are  used  in  medicine  in  various  parts 
of  the  world. 

Asarum  canadense  (Canada  snakeroot  or  wild  ginger)  is  a 
plant  common  in  the  Northern  United  States  and  Canada  (Fig. 
288).  The  long  and  slender  rhizomes  are  used  in  medicine. 
They  are  5  to  15  cm.  long,  about  2  mm.  thick,  more  or  less  bent 
and  curved,  purplish-brown  externally ;  whitish  internally ;  the 
bark  is  thick,  wood  with  about  12  fibrovascular  bundles,  pith  large  ; 
the  odor  is  aromatic ;  the  taste  pungent  and  bitter.  The  drug  con- 
tains 2  to  3  per  cent,  of  a  volatile  oil  containing  a  fragrant  body, 
asarol ;  a  pungent,  fragrant  resin ;  a  yellow  coloring  principle 
which  is  colored  dark  green  with  ferric  salts ;  and  starch.  The 
volatile  oil  obtained  from  A.  europccum  contains  a  principle  (asa- 
rone)  which  forms  irritating  vapors  on  heating. 

X.    ORDER  POLYGON  ALES. 

This  order  is  represented  by  a  single  family,  the  POLYGONACE^: 
cr  Buckwheat  family.  The  plants  are  mostly  herbs,  but  include 
some  twining  vines  and  shrubs.  The  leaves  are  simple,  mostly 
entire,  and  characterized  by  having  a  stipulate  appendage  (ocrea) 
which  sheaths  the  stem.  The  flowers  are  small,  perfect,  and  with 
a  2-  to  6-parted  perianth.  The  fruit  is  a  3-  to  4-angled  akene.  The 
embryo  is  either  straight  or  curved,  and  the  endosperm  is  mealy. 


CLASSIFICATION  OF  ANGIOSPERMS.  521 


FIG.  287.  Southern  serpentaria  (Aristolochia  reticulata)  showing  the  cordate,  reticu- 
lately-veined  leaves,  and  the  clusters  of  irregular  flowers  on  the  lower  part  of  the  stem. 
—After  Carson. 


522 


A  TEXT-BOOK  OF  BOTANY. 


RHeum  officinale  is  the  source  of  the  "  South  China  "  rhubarb 
from  Szechwan,  Kanzu,  and  Shensi.  The  plant  is  a  perennial  herb 
resembling  the  garden  rhubarb.  The  rhizome  is  vertical  and 
gives  rise  to  a  leafy  branch  terminated  by  the  inflorescence,  which 
is  a  panicle.  The  leaves  are  large,  with  a  sub-cylindrical  petiole, 


FIG.  288.  Wild  Ginger  (Asarum  canadense).  A,  showing  habit  of  plant,  consisting  of 
underground  root-stock,  the  kidney-shaped  leaves  on  long  petioles,  and  the  short  peduncled, 
bell-shaped  flower  which  develops  close  to  the  ground;  B,  longitudinal  section  of  flower, 
and  C,  a  transverse  section  of  flower. — Bicknell,  in  Bulletin  Torrey  Bot.  Club,  Nov.,  1897. 

a  cordate  or  orbicular  lamina  which  is  either  entire  or  coarsely 
and  irregularly  dentate.  There  are  several  nearly  related  species 
which  also  yield  the  drug.  Rheum  pahnatum  of  Northern  China 
has  leaves  which  are  lobed  or  deeply  incised,  which  character  is 
especially  marked  in  the  variety  tanguticum.  Rheum  Rhaponti- 
cum,  which  yields  English  rhubarb,  has  leaves  which  are  heart- 


CLASSIFICATION  OF  ANGIOSPERMS.  523 

shaped  at  the  base  and  with  a  more  or  less  irregularly  undulate 
margin.  All  of  these  species  are  more  or  less  common  in  culti- 
vation in  botanical  gardens  in  Europe. 


FIG.  289.  Curled  dock  (Rumex  crispus}  showing  two  of  the  lower,  long-petioled,  oblong- 
lanceolate  and  wavy-margined  leaves,  and  a  flowering  branch,  the  upper  leaves  of  which 
are  narrowly-oblong  and  short-petioled. 

Rumex  crispus  or  curled  dock  is  a  perennial  herb  growing  in 
fields  and  waste  places  in  the  United  States  and  parts  of  Canada. 


524 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  290.  Field  or  sheep  sorrel  (Rumex  acetosella) ,  a  common  weed  containing  a 
sour  juice  and  growing  in  open  fields;  i  to  3  dm.  high,  having  narrow-lanceolate  or  halberd- 
shaped  leaves,  and  somewhat  reddish  flowers  in  a  panicled  raceme. — After  Brown. 

The  leaves  are  oblong-lanceolate,  with  an  undulate  margin  and 
rather  long  petiole.  The  flowers  have  a  6-parted,  dark  green 
perianth,  and  are  perfect  or  polygamo-dicecious.  The  fruit  is  a 


CLASSIFICATION  OF  ANGIOSPERMS.  525 

dark  brown,  cordate-winged,  3-angled  akene.     The  dried  root  is 
somewhat  fusiform,  reddish-brown,  and  with  a  bitter,  astringent 


FIG.  291.  Polygonum  pennsylvanicum  (Fam.  Polygonaceae),  one  of  about  30  species 
of  knotweeds,  being  common  in  waste  places,  all  herbaceous,  and  characterized  by  the  leaves 
having  sheathing  stipules.  Typical  of  this  group  is  P.  pennsylvanicum,  having  lanceolate 
leaves  and  short,  erect  terminal  spikes  with  bright  rose-colored  flowers. — After  Brown. 

taste.    It  contains  chrysophanic  acid,  tannin,  calcium  oxalate,  and 
some  of  the  other  constituents  found  in  rhubarb  (Fig.  289). 

Rumex  Acetosella  (field  or  sheep  sorrel),  is  a  slender  annual 
herb  with  hastate  leaves,  having  flowers  in  compound  racemes. 


526 


A  TEXT-BOOK  OF  BOTANY. 


The  leaves  contain  oxalic  acid,  both  free  and  in  combination  with 
calcium  and  potassium  (Fig.  290). 


FIG.  292.  Buckwheat  (Fagopyrum  esculentuni):  A,  transverse  section  of  grain  showing 
pericarp  (c),  endosperm  (n)  and  slender  coiled  embryo  (e);  B,  transverse  section  of  portion 
of  grain  showing  epicarp  (e),  fibrous  layer  (f),  pigment  layer  (p),  outer  epidermis  of  spermo- 
derm  (o),  aleurone  cells  (a),  endosperm  cells  containing  starch  (n) ;  C ,  surf  ace  view  of  cells 
of  epicarp;  D,  isolated  fibers  of  pericarp;  E.  surface  view  of  aleurone  cells;  F,  isolated  par- 
enchyma cells  of  endosperm  filled  with  starch  grains  as  seen  in  buckwheat  flour;  G,  appear- 
ance of  starch  grains  when  mounted  in  oil  and  viewed  with  polarized  light;  H,  swollen  and 
altered  starch  grains  which  are  two  to  three  times  the  size  of  the  normal  grains. 

Tannin  is  obtained  from  a  number  of  the  plants  belonging  to 
the  Polygonacese,  as  the  root  of  Rumex  hymenosepalus  of  Texas 


CLASSIFICATION  OF  ANGIOSPERMS.  5*7 

which  is  known  as  CANAIGRE;  the  rhizome  of  Polygonum  bistorta 
of  Europe  which  yields  the  drug  BISTORTA. 

Polygonum  cuspidatum  of  the  gardens  contains  emodin ;  poly- 
gonin,  a  glucoside  yielding  emodin ;  and  probably  emodin  methyl 
ether.  Rumex  ecklonianus  of  South  Africa  contains  emodm,  a 
volatile  oil  and  a  resin.  The  latter  consists  of  emodin  monomethyl 
ether;  chrysophanic  acid,  physosterol  (resembling  rhamnol),  etc. 
Polygonum  Hydropiper  and  P.  aviculare,  both  common  in  the 
United  States,  are  poisonous  to  sheep. 

A  number  of  the  plants  of  this  family  yield  food  products. 
Buckwheat  is  the  fruit  of  Fagopyrum  csculentum  indigenous  to 
Central  Asia  and  cultivated  in  many  parts  of  the  world  (Fig.  292). 

Some  are  also  cultivated  as  ornamental  plants,  as  the  Prince's 
feather  (Polygonum  orientale). 

XI.    ORDER   CHENOPODIALES   OR   CENTROSPERM^. 

This  order  includes  seven  families,  in  all  of  which  the  embryo 
is  curved  or  coiled,  and  the  reserve  consists  chiefly  of  perisperm. 

a.  CHENOPODIACE^E  OR  GOOSEFOOT  FAMILY.- 
The  plants  are  annual  or  perennial  herbs  with  simple  leaves  and 
small  perfect  flowers,  the  fruit  being  a  utricle.  The  fruits  of  a 
number  of  the  group  contain  volatile  oil,  and  are  used  in  medi- 
cine, as  the  common  woTmseed  (Chenopodiuin  ambrosioides 
anthelminticum) ,  which  is  found  in  waste  places  in  the  United 
States.  Most  of  the  oil  is  distilled  in  Maryland  and  is  known  in 
commerce  as  "  Baltimore  oil." 

Che  no  podium  mejcicanum  yields  saponin.  Atriplex  hortensis 
of  Tartary  yields  indigo.  The  ash  of  very  many  species  of  Atriplex 
as  well  as  genera  of  the  Chenopodiacese  yields  soda.  The  seeds 
of  several  species  are  edible,  as  of  Chenopodium  viride  of  Europe 
and  Asia,  C.  Quinoa  of  Chile,  etc.  Seeds  of  Spinacia  tetandra 
of  the  Orient  are  used  in  bread-making. 

A  number  of  species  are  used  as  garden  vegetables,  as  spinach 
(Spinacia  oleracea)  and  beet  (Beta  vulgaris). 

The  SUGAR  BEET  (Beta  vulgaris  Rapa),  which  contains  from 
4  to  15  per  cent,  of  cane  sugar  (sucrose),  is  largely  cultivated  in 
Germany,  as  well  as  to  some  extent  in  the  United  States,  and  is 
an  important  source  of  cane  sugar.  While  the  juice  of  the  beet 


528  A  TEXT-BOOK  OF  BOTANY. 

contains  a  larger  amount  of  nitrogenous  substances  than  that  of 
the  sugar  cane,  it  is  practically  free  from  invert  sugar. 

b.  AMARANTACE^E.— The  plants  are  weed-like  and  much 
resemble  the  Chenopodiacese.    They  yield  anthelmintic  principles, 
edible  seeds,  and  the  leaves  of  a  number  of  species  are  used  as 
vegetables.    The  ash  yielded  by  some  species  contains  potash,  as 
Achyranthes  aspera  and  Amaranthus  ruber.    Some  are  ornamental 
plants    having    a    fasciated    inflorescence,    as    the    Cock's-comb 
(Celosia  cristata). 

c.  NYCTAGINACE^E  OR  FOUR-O'CLOCK  FAMILY .- 
The  plants  are  mostly  herbs  growing  in  America.    The  leaves  are 
entire  and  simple,  and  the  flowers  are  regular  and  in  terminal  or 
axillary  clusters.    The  perianth  consists  of  a  4-  to  5-lobed  corolla- 
like  calyx.    The  most  common  representative  of  this  family  is  the 
Marvel-of-Peru  or  four-o'clock  (Mirabilis  Jalapa).     While  this 
plant  is  an  annual  in  the  United  States,  in  the  Tropics  the  tuberous 
root  is  used  as  a  substitute  for  jalap,  and  is  sometimes  sold  for  it. 
The  seeds  of  this  plant  are  edible,  as  are  also  the  leaves  of  several 
species,  as  of  Bocrhavia  erecta,  which  are  used  as  green  vegetables. 
Some  members  of  the  group,  as  Bougainvillea  spectabilis,  are 
handsome  plants  with  bright  rose-colored  bracts  which  envelop 
the  small  greenish  flowers. 

d.  PHYTOLACCACE^E.— The    plants    of    this    family    are 
mostly  tropical  and  are  represented  in  this  region  by  only  one 
species,  namely,  the  common  poke  (Phytolacca  decandra),  the  root 
and  fruit  of  which  are  used  to  some  extent  in  medicine.    This  is  a 
succulent,  branching  herb  I  to  4  M.  high,  having  a  large  perennial 
root.     The  stem  is  hollow  except  for  the  thin,  papery  partitions. 
The  leaves  are  simple,  ovate-lanceolate,  petiolate.     The  flowers 
are  in  racemes  and  characterized  by  having  ten  stamens.     The 
fruit  is  a  dark  purple,  juicy  berry  (Fig.  293). 

The  roots  of  this  species  as  well  as  others  contain  powerful 
drastic  principles,  as  Pircunia  littoralis  and  Anisomeria  drastica 
of  Chile.  Phytolacca  abyssinica  contains  saponin,  and  a  red  color- 
ing principle  is  found  in  the  berries  of  Phytolacca  decandra  and 
Rivinia  tinctoria  of  Venezuela.  The  leaves  of  some  species  of 
Phytolacca  are  used  as  greens. 

e.  AIZOACE^L. — This  is  a  group  of  mostly  tropical  plants, 


CLASSIFICATION  OF  ANGIOSPERMS.  529 


FIG.  293.  Poke  weed  (Phytolacca  decandra),  a  common  weed  growing  in  low  grounds 
and  waste  places.  The  plant  is  a  perennial  herb,  usually  sending  up  from  a  large,  fleshy 
root  a  number  of  stout  stalks,  i  to  3  M.'high;  the  leaves  are  ovate-oblong,  and  opposite  which 
may  arise  the  racemes  of  whitish  flowers.  The  roots  are  quite  frequently  mistaken  for 
parsnips,  and  when  eaten  may  cause  serious  illness.  The  young  shoots  and  leaves  are 
sometimes  gathered  in  the  spring  and  may  be  used  for  a  table  vegetable.  The  juice  of  the 
berries  is  said  to  have  been  used  in  Portugal  to  color  Port  wine. — After  Brown. 

very  many  of  them  having  fleshy  leaves  and  adapted  to  arid  re- 
gions. Many  of  the  plants,  particularly  those  belonging  to  the 
genus  Mesembryanthemum,  are  much  prized  on  account  of  their 

34 


530 


A  TEXT-BOOK  OF  BOTANY. 


beautiful  flowers,  which  expand  only  in  the  sunshine.  The  com- 
mon ice-plant  of  the  gardens,  so  called  because  of  the  numerous 
glistening  globules  of  water  which  cover  the  leaves,  is  M.  crystal- 


FiG.  294.  Soapwort,  Bouncing  Bet  (Saponaria  officinalis),  a  perennial  herb  growing 
to  a  height  of  3  to  6  dm.  and  producing  opposite,  entire  leaves,  and  cymose  clusters  of  rose- 
colored  flowers,  commonly  double.  This  plant  has  been  more  or  less  cultivated;  it  has, 
however,  escaped  from  the  garden,  and,  in  spite  of  its  beauty,  has  become  a  troublesome 
weed  in  some  places.  The  plant  contains  saponin  and  therefore  forms  a  lather  with  water. 
It  has  been  used  as  a  detergent. — After  Brown. 

linum.  This  plant  as  well  as  other  species  of  Mesembryanthemum 
are  used  in  medicine.  The  ashes  yielded  by  the  plants  of  this 
family  also  contain  soda.  The  seeds  of  some  species  of  Mesem- 


CLASSIFICATION  OF  ANGIOSPERMS.  531 

bryanthemum  as  well  as  other  members  of  this  family  are  edible, 
and  the  leaves  of  some  species  are  used  as  vegetables  like  lettuce. 

/.  PORTULACACEyE.— The  plants  are  fleshy  or  succulent 
herbs  mostly  indigenous  to  America.  The  two  common  represen- 
tatives are  the  spring  beauty  (Claytonia  virginica),  the  tubers  of 
which  are  rich  in  starch,  and  purslane  (Portulaca  oleracea),  some- 
times used  as  a  green  vegetable.  The  seeds  of  the  latter  plant  as 
well  as  of  other  species  of  Portulaca  are  used  in  medicine. 

g.  CARYOPHYLLACEyE. — The  plants  are  annual  or  peren- 
nial herbs,  often  swollen  at  the  nodes,  with  opposite,  entire  leaves, 
and  usually  perfect  regular  flowers.  The  perianth  has  a  distinct 
corolla  of  4  or  5  petals.  The  fruit  is  a  capsule  and  the  seeds  are 
half  anatropous.  The  plants  are  most  abundant  in  the  northern 
hemisphere ;  and  some  of  them  are  quite  showy,  as  the  CARNATION 
(Dianthus  caryophyllus)  and  pinks  (Dianthus  species)  and  the 
cultivated  pink  or  Sweet  William  (D.  barbatus).  A  number  of 
the  members  of  this  group  contain  saponin,  as  Bouncing  Bet 
(Saponaria  offtcinalis) ,  which  is  naturalized  in  the  United 
States  (Fig.  294),  Gypsophila  Struthium  of  Spain  and  other 
species  of  this  genus,  as  well  as  species  of  Lychnis  and  Her- 
niaria.  The  leaves  of  Paronychia  argentea  are  used  in  Morocco 
as  a  substitute  for  tea.  The  roots  of  Scleranthus  peren- 
nis  of  Eastern  Europe  are  inhabited  by  an  insect  (Coccus 
polanica)  which  is  used  in  the  preparation  of  a  red  dye.  The 
fleshy  stitch- wort  (Alsine  crassifolia)  of  Europe  and  the  United 
States  is  poisonous  to  horses. 

XII.    ORDER  RANALES. 

The  plants  are  mostly  herbs,  but  include  some  shrubs  and  trees, 
and  comprise  eight  families  of  economic  importance. 

a.  NYMPH^ACE^:  OR  WATER  LILY  FAMILY.— 
These  are  aquatic  perennial  herbs  with  thick  root-stocks  and 
floating,  peltate  leaves.  The  flowers  are  perfect  and  have  large 
petals.  The  seeds  are  enclosed  in  an  aril,  and  the  embryo  has  fleshy 
cotyledons. 

Nuphar  luteum  of  Europe  and  Middle  Asia  contains  the  alka- 
loid nupharine  and  tannin,  the  latter  of  which  splits  into  ellagic 
and  gallic  acids.  The  yellow  pond  lily  (Nymphoca  advena)  of  the 


532  A  TEXT-BOOK  OF  BOTANY. 

United  States  contains  similar  principles.  The  seeds  and  rhizomes 
are  rich  in  starch  and  are  used  as  food,  in  some  cases  starch  being 
manufactured  from  them,  as  of  various  species  of  Nymphcca, 
Nelumbo  (Lotus)  and  Victoria,  and  Euryale  ferox. 

b.  RANUNCULACE^  OR  CROWFOOT  FAMILY.— 
These  are  annual  or  perennial  herbs  with  simple  or  compound 
leaves,  regular  or  irregular  flowers,  and  fruits  which  are  akenes, 
follicles,  or  berries. 


FIG.  295.  Fruiting  top  of  Golden  Seal  (Hydrastis  canadensis),  showing  the  two  large 
palmate  leaves,  above  one  of  which  is  a  berry-like  fruit  which  is  bright  red  when  ripe. 

Hydrastis  canadensis  yields  the  official  drug  hydrastis.  From 
a  short,  thick,  horizontal  rhizome  with  numerous  slender  roots 
rises  a  short  stalk  with  a  few  palmately  lobed,  reniform,  petiolate, 
pubescent  leaves.  The  flowers  are  small,  solitary  and  greenish- 
white,  and  the  fruit  is  a  head  of  crimson  berries  somewhat  resem- 
bling the  raspberry  (Fig.  295). 

Cimicifuga  racemosa  (black  cohosh  or  black  snakeroot)  yields 
the  official  drug  cimicifuga.  This  is  a  tall  perennial  herb  with  large 
knotty  rhizome,  large  decompound  leaves,  and  a  long  raceme  of 
white  flowers  (Fig.  296). 


CLASSIFICATION  OF  ANGIOSPERMS. 


533 


FIG.  296.  A  group  of  transplanted  wild  plants  with  a  plant  of  Ctmicifuga  racemosa 
in  the  foreground,  showing  the  characteristic,  large,  decompound  leaves  and  long  raceme  of 
flowers. 

Aconitum  Napellus  yields  the  official  drug  aconite  (Fig.  186). 
This  is  a  perennial  herbaceous  plant  indigenous  to  Europe  and 
extensively  cultivated.  From  a  tuberous  root  arises  a  simple  leafy 


534 


A  TEXT-BOOK  OF  BOTANY. 


stem  with  palmately  lobed  or  divided  leaves,  and  large,  irregular, 
blue  flowers  which  form  a  rather  loose  panicle  (Fig.  297).  The 
sepals  are  5  in  number,  the  posterior  upper  one  being  large  and 


E 


FIG.  297.  Acomtum  Napellus .  A,  one  of  the  long-petiolate,  divided  leaves;  B,  epi- 
dermal cells  of  lower  surface;  c,  an  epidermal  cell  of  the  upper  surface;  D,  transverse  sec- 
tion through  one  of  the  principal  veins  showing  two  fibrovascular  bundles,  and  strongly 
collenchymatic  cells  beneath  the  lower  epidermis;  E,  one  of  the  few  hairs  from  the  petiole; 
F,  lignified  bast  fibers  surrounding  the  sieve  in  the  petiole;  G,  longitudinal  section  through 
fibrovascular  bundle  showing  spiral  and  reticulate  tracheae  (t),  bast  fibers  (b)  and  some 
of  the  collenchyma  cells  (c),  those  at  the  left  exhibiting  longitudinal  pores  which  give 
a  crystal-like  effect. 

helmet-shaped.  The  petals  are  2  to  5  and  rather  small ;  the  two 
posterior  or  upper  ones  which  are  hooded  and  concealed  in  the 
helmet-shaped  sepal  are  nectar-secreting  (Fig.  223,  E).  The  fruit 
is  a  follicle  and  contains  numerous  small  seeds. 


CLASSIFICATION  OF  ANGIOSPERMS.  535 


FIG.  298.  Wood  anemone,  wind  flower  (Anemone  quinque  folia) ,  one  of  the  earliest 
flowering  woodland  plants.  It  is  a  low,  slender  plant  with  3  trifoliate  leaves  forming  an 
involucre,  from  the  junction  of  which  arises  a  peduncle,  bearing  a  solitary  flower.  The 
sepals  vary  in  number  as  well  as  in  color;  there  are  generally  5,  which  are  usually  whitish, 
or  slightly  tinged  with  purple. — After  Brown. 

Delphinium  Staphisagria,  which  yields  the  official  staphisagria 
or  stavesacre,  is  a  handsome,  tall,  biennial  larkspur,  with  dark 
green,  palmate  5-  or  7-lobed  leaves  and  blue  or  purplish  flowers  in 


536 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  299.  Wild  Columbine  (Aquilegia  canadensis),  one  of  the  most  interesting  plants 
of  the  Ranunculaceae.  It  grows  in  the  crevices  of  rocks  and  in  open  woods,  and  is  a  very 
striking  plant,  with  its  5  long-spurred,  scarlet  petals.  A  number  of  species  of  Aquilegia 
are  cultivated,  and  their  flowers  show  considerable  variation  in  form  and  color. — After 
Brown. 


racemes.     The  flowers  are  zygomorphic  and  somewhat  resemble 
those  of  Aconite. 


CLASSIFICATION  OF  ANGIOSPERMS.  537 

PULSATILLA,  which  was  formerly  official,  is  obtained  from  sev- 
eral species  of  Anemone  growing  in  Europe.  These  are  perennial 
herbs  (Fig.  206)  with  basal  leaves  which  are  deeply  lobed  or 
dissected,  those  of  the  stem  forming  a  kind  of  involucre  near  the 
flower.  The  flowers  are  rather  large  and  with  numerous  petaloid 
sepals.  The  fruit  is  a  densely  woolly  achene  in  those  species  which 
are  used  in  medicine.  The  entire  plant  is  used  and  contains  an 
acrid  volatile  oil,  the  principal  constituent  of  which  is  an  anemone 
camphor  (anemonol).  The  latter  is  easily  decomposed  into 
anemonon,  which  on  fusion  becomes  exceedingly  acrid.  Similar 
principles  are  found  in  other  species  of  Anemone  as  well  as  in 
certain  species  of  Ranunculus  (buttercup)  and  Clematis  Vitalba  of 
Europe. 

Very  many  of  the  other  Ranunculacese  contain  active  princi- 
ples. The  glucoside  helleborein,  which  resembles  digitalin  in  its 
medicinal  properties,  is  found  in  Helleborus  niger,  the  BLACK 
HELLEBORE  of  Europe,  and  probably  in  other  species  of  Helleborus, 
as  well  as  in  Actcea  spicata,  the  baneberry  of  Europe,  and  Adonis 
vernalis,  the  false  hellebore  of  Europe  and  Asia. 

c.  BERBERIDACE^:  OR  BARBERRY  FAMILY.— The 
plants  of  this  family  are  herbs  or  shrubs  with  simple  or  compound 
leaves,  and  flowers  either  single  or  in  racemes  (Figs.  134,  E; 
81,  T).  The  fruit  is  a  berry  or  capsule. 

Herberts  Aquifolimn  (trailing  mahonia)  yields  the  unofficial 
drug  berberis.  It  is  a  low,  trailing  shrub  with  3-  to  7-compound, 
scattered  leaves.  The  leaflets  vary  from  oval  to  nearly  orbicular, 
are  obtuse  at  the  apex,  slightly  cordate  at  the  base,  finely  reticulate, 
and  spinose-dentate.  The  flowers  are  yellow  and  in  dense  ter- 
minal racemes.  The  fruit  is  a  blue  or  purplish  berry. 

Caulophyllum  thalictroides  or  blue  cohosh  of  the  Eastern 
United  States  is  a  perennial  herb  with  a  thick  rhizome  and  large 
ternately  compound  leaves  (Fig.  300).  The  flowers  are  small 
and  greenish-purple.  The  fruit  is  peculiar  in  that  it  resembles  a 
berry  and  consists  only  of  blue,  globular,  naked  seeds,  the  pericarp 
being  ruptured  and  falling  away  soon  after  fertilization.  The 
rhizome  and  roots  were  formerly  official.  It  is  a  horizontal,  much 
branched  rhizome  with  broad,  concave  stem-scars,  and  numerous 
roots ;  it  is  grayish-brown  externally,  sweetish,  slightly  bitter  and 


538 


A  TEXT-BOOK  OF  BOTANY. 


somewhat  acrid.  The  drug  contains  an  acrid,  saponin-like  gluco- 
side,  leontin  ;  a  crystalline  alkaloid,  caulophylline  ;  two  resins  ;  and 
starch.  For  analysis  of  the  seeds  see  Chem.  News,  1908,  p.  180. 

Podophyllum  peltatum  or  May  apple  is  the  source  of  the  official 
podophyllum.  This  is  an  early,  herbaceous,  low,  perennial  plant 
forming  large  patches  by  reason  of  its  long  dichotomously  branch- 


FIG.  300.     A  group  of  transplanted  plants,  showing  in  the  upper  portion 
a  fruiting  plant  of  blue  cohosh  (Caulophyllum  thalictroides') . 

ing  rhizome  (Fig.  182).  It  forms  two  kinds  of  branches,  one 
bearing  a  single,  peltate,  5-  to  7-lobed  leaf ;  and  another  bearing 
in  the  axil  of  two  similar  leaves  a  white  flower  which  gives  rise 
to  a  large,  yellowish,  ovoid  berry  which  is  edible. 

d.  MENISPERMACE^:  OR  MOONSEED  FAMILY.— 
The  plants  are  climbing  or  twining,  herbaceous  or  woody  vines 
with  simple,  entire  or  lobed  leaves  and  small,  greenish-white  dice- 


CLASSIFICATION  OF  ANGIOSPERMS.  539 

cious  flowers.  The  fruit  is  a  drupe  and  contains  a  characteristic 
crescent-shaped  seed. 

Menispermum  canadense  or  Canada  moonseed  yields  the  drug 
menispermum  which  was  formerly  official.  It  grows  in  the  North- 
ern United  States  and  Canada  and  is  a  high-climbing  vine  with 
broadly  ovate,  cordate  and  3-  to  7-lobed  leaves  (Fig.  180).  The 
flowers  are  in  panicles  giving  rise  to  a  characteristic  cluster  of 
bluish-black  berries. 

The  rhizome  occurs  in  pieces  which  are  5  to  7  dm.  long  and 
2  to  5  mm.  in  diameter;  externally  it  is  longitudinally  wrinkled, 
of  a  yellowish-brown  color  and  somewhat  resembles  Sarsaparilla. 
In  transverse  section,  however,  it  is  very  distinct  (Fig.  194).  The 
drug  has  a  bitter  taste  and  contains  a  bitter  alkaloid  menispine, 
berberine  and  starch.  In  addition  it  contains  the  alkaloid  oxyacan- 
thine  which  is  also  found  in  Berberis  vulgaris  of  Europe  and  the 
West  Indies. 

Jateorhiza  palmata  yields  the  official  drug  calumba  (columbo). 
The  plant  is  a  herbaceous  climber  somewhat  resembling  Meni- 
spermum, the  leaves  being  more  decidedly  lobed.  The  flowers 
form  long  racemes. 

Chondrodendron  tomentosum,  the  source  of  the  unofficial  drug 
pareira,  is  a  high  woody  twiner.  The  leaves  are  large,  petiolate, 
broadly  ovate  or  rounded,  slightly  cordate,  and  densely  tomentose 
on  the  lower  surface. 

Anamirta  paniculata  is  a  woody  climber  of  the  East  Indies. 
The  fruits,  known  as  fishberries  or  COCCULUS,  are  used  as  a  fish 
poison  by  the  natives  and  contain  the  neutral  principle  picrotoxin. 

Very  many  other  plants  of  the  Menispermaceae  contain  power- 
ful toxic  principles  and  are  used  as  fish  poisons  and  as  antidotes 
to  snake  poison.  Several  species  of  Abuta  are  used  in  the  prepara- 
tion of  curare  poison. 

e.  MAGNOLIACE^E  OR  MAGNOLIA  FAMILY.— The 
plants  are  mostly  trees  or  shrubs  and  are  represented  in  the 
United  States  by  the  magnolias  and  tulip  tree  (Liriodendron 
Tulipifera).  The  latter  is  a  magnificent  tree  with  characteristic 
leaves  (Fig.  204)  and  large,  fragrant,  orange-colored,  tulip-like 
flowers. 

The  plants  of  this  family  contain  a  variety  of  constituents. 


540  A  TEXT-BOOK  OF  BOTANY. 

Ethereal  oils  containing  anethol  and  resembling  those  of  anise 
are  found  in  the  fruit  of  Illicium  anisatum  (I.  verum)  or  STAR 
ANISE,  a  small  evergreen  tree  growing  in  the  mountains  of  South- 
ern China.  A  volatile  oil  with  a  disagreeable  odor  is  found  in  a 
closely  related  species  /.  religiosum  (Shikimi)  of  Japan.  The 
fruit  of  the  latter  plant  is  known  as  JAPANESE  STAR  ANISE  and 
contains  in  addition  a  poisonous  neutral  principle.  The  fruits  of 
both  star  anise  (Illicium)  and  the  Japanese  star  anise  are  made  up 
of  6  to  S  radially  arranged  follicles,  which  are  dark  brown,  dehis- 
cent on  the  upper  (ventral)  surface  and  each  contains  a  single, 
brown,  shiny  seed.  Star  anise  has  an  odor  and  taste  resembling 
anise.  Japanese  star  anise  has  a  bitter  taste  and  in  addition  is 
brownish-black,  very  woody  and  strongly  beaked. 

Volatile  oils  are  also  found  in  the  flowers  of  the  various  species 
of  Magnolia  and  in  Michelia  Champaca  found  in  the  Malay  Archi- 
pelago and  cultivated  in  India  and  Brazil,  and  in  M.  nilagirica  of 
India,  the  latter  being  used  in  perfumery. 

Winter's  bark  is  derived  from  Drimys  Winteri,  a  shrub  of 
South  America.  It  occurs  in  quills  which  are  from  5  to  10  mm. 
thick;  externally  it  is  grayish-brown  and  covered  with  numerous 
lichens ;  the  fracture  is  short,  the  broken  surface  being  marked 
by  stone  cells  and  resin  canals;  the  odor  is  fragrant;  taste  aro- 
matic, pungent  and  bitter.  The  drug  contains  a  volatile  oil  which 
consists  essentially  of  a  hydrocarbon  known  as  winterin;  it  also 
contains  a  resin. 

A  crystalline  principle  magnolin,  a  glucoside  and  a  volatile  oil 
are  found  in  Magnolia  macro phylla  (or  cucumber-tree  of  the 
Southern  States)  and  M.  tripetala  or  umbrella  tree  growing 
southward  from  Pennsylvania.  A  bitter  principle  liriodendrin,  a 
volatile  oil,  an  alkaloid,  and  a  glucoside  are  found  in  the  tulip 
poplar  or  tulip  tree. 

The  bitter  and  aromatic  bark  of  Michelia  montana  of  Java  is 
used  like  cascarilla  (Euphorbiacese).  A  bitter  resin  is  found  in 
the  fruit  of  Talauma  Plumieri  of  the  Antilles. 

A  glucoside  which  dissolves  the  blood  corpuscles  is  found  in 
Talauma  macrocarpa  of  Mexico.  A  red  coloring  principle  soluble 
in  water  occurs  in  the  leaves  of  Michelia  Tsiampaca  of  Java.  The 
fruits  of  Schizandra  propinqua  of  Nepal  and  Kadsura  Rox- 


CLASSIFICATION  OF  ANGIOSPERMS. 


54i 


burghiana  of  Japan  contain  considerable  mucilage  and  are  edible. 
The  latter  plant  is  also  used  as  a  hair-restorer.  From  the  ash  of 
Schizandra  chincnsis  of  China  and  Japan  sodium  chloride  is 
obtained. 

The  flowers  of  Magnolia  Juglans  are  used  to  flavor  tea  and  the 


FIG.  301.  North  American  papaw  (Asimina  triloba):  A,  branch  showing  lateral 
nodding  flower  and  the  large,  pinnately- veined,  entire  leaves :  B.  section  of  the  oblong, 
3-seeded  berry;  C,  D,  seeds,  the  one  in  longitudinal  section. — After  Baillon. 

leaves  of  Talauma  ovata  are  used  as  a  substitute  for  tea  in  Brazil. 
/.  ANONACE^  OR  CUSTARD-APPLE  FAMILY.— 
These  are  shrubs  or  small  trees  chiefly  inhabiting  warm-temperate 
and  tropical  regions.  They  yield  very  many  economic  products. 
The  fruit  of  Xylopia  brasilensis  is  used  as  a  substitute  for  cubeb. 
Some  yield  fruits  having  an  aroma  similar  to  that  of  nutmeg,  as 


542 


A  TEXT-BOOK  OF  BOTANY. 


Monocarpia  Blancoi  of  Africa  and  Jamaica.  The  flowers  of 
Cananga  odorata  of  tropical  countries  are  used  in  the  preparation 
of  a  pomade  from  which  the  perfume  YLANG-YLANG  is  made. 
Ethereal  oils  are  also  found  in  other  species,  as  Uncna  ligularis 
of  Ambyona,  the  seeds  of  which  are  used  in  perfumery.  The  bark 
of  Popowia  pisocarpa  of  Java  contains  an  alkaloid. 


FIG.  302.  Nutmeg  trees  growing  in  Singapore.  The  trees  are  handsome,  evergreen 
shrubs,  extensively  cultivated  in  the  East  Indies,  and  to  some  extent  in  tropical  America. — 
Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

The  seeds  of  Xylopia  salicifolia  of  Trinidad  and  X.  muricata  of 
Jamaica  are  very  bitter,  as  are  also  the  wood  and  bark  of  X.  glabra 
of  the  West  Indies. 

The  seeds  of  Asimina  triloba,  the  North  American  papaw 
(Fig.  301),  contains  an  emetic  principle.  This  plant  should  not 
be  confounded  with  Carica  Papaya  (Caricacese)  which  contains 
the  ferment  papain. 

Many  of  the  Anonacese  yield  large  succulent  fruits,  some  of 
which  are  edible,  as  the  sugar  apple  obtained  from  Anona  squa- 


CLASSIFICATION  OF  ANGIOSPERMS. 


543 


mosa  and  CUSTARD  APPLE  from  A.  reticulata  both  abundant  in  the 
Tropics.  The  fruit  of  A.  muricata  sometimes  weighs  as  much  as 
two  kilograms. 

g.  MYRISTICACE^:     OR     NUTMEG     FAMILY.— This 
family  is  represented  by  the  single  genus  Myristica.     Nutmeg 


FIG.  303.     Young  plant  of  Cinnamomum  zeylanicum  grown  from  cutting. 

(Fig.  302)  and  mace  are  obtained  from  Myristica  fragrans,  an 
evergreen  tree  with  ovate,  petiolate,  coriaceous,  entire  and 
pinnately-veined  leaves.  The  flowers  are  small,  yellow  and  dice- 
cious.  The  fruit  is  a  berry  having  somewhat  the  shape  and  size 
of  the  green  fruit  of  black  walnut.  It  has  a  line  of  dehiscence, 
and  when  ripe  is  yellow.  The  arillode  of  the  seed  constitutes  MACE, 


544  A  TEXT-BOOK  OF  BOTANY. 

while  the  kernel  is  th£  NUTMEG,  the  pericarp  of  the  fruit  and  coat 
of  the  seed  being  rejected. 

h.  LAURACE^:  OR  LAUREL  FAMILY.— The  members 
of  this  family  are  chiefly  shrubs  and  trees  which  are  distributed 
mostly  in  the  Tropics,  although  a  few  are  found  in  the  temperate 
zones  (Fig.  280,  F). 

Sassafras  officinale. — This  is  a  tree  common  in  the  eastern  and 
central  portion  of  the  United  States  and  is  characterized  by  its 
rough  bark  and  its  I-  to  3-lobed  leaves,  from  whence  it  received 
its  former  name  Sassafras  variifolium  (Fig.  203).  The  flowers 
are  yellow,  dioecious  and  appear  in  the  spring  before  the  leaves. 
The  fruit  is  an  oblong,  blue  drupe. 

Cinnanwmum  zeylanicum,  which  is  the  source  of  the  Ceylon 
cinnamon  (Fig.  304),  is  a  small,  handsome,  evergreen  tree  with 
opposite,  coriaceous,  broadly  lanceolate,  3-  to  5~nerved  leaves  (Fig. 
303).  The  flowers  are  yellowish- white,  hermaphrodite,  or  both 
pistillate  and  staminate.  The  fruit  is  a  black,  ovoid  berry.  The 
oil  of  Ceylon  cinnamon  from  the  bark  and  branches  is  charac- 
terized by  its  content  of  cinnamic  aldehyde;  from  the  leaves  by 
eugenol;  and  from  the  root  bark  by  camphor.  C.  Cassia  which 
yields  Cassia  cinnamon  is  a  tree  growing  in  China,  Sumatra,  and 
cultivated  in  Java.  It  has  long,  oblong-lanceolate  leaves  which  are 
pubescent  on  the  lower  surface.  Cassia  cinnamon  (bark)  is  also 
obtained  from  Cassia  Burmanni.  Saigon  cinnamon  (see  Vol.  II) 
is  derived  apparently  from  wild  trees  growing  in  the  mountainous 
regions  of  Anam,  the  botanical  origin  of  which  has  not  been 
determined. 

The  volatile  oils  of  the  members  of  the  Lauraceae  vary  con- 
siderably in  composition.  In  addition  to  the  oils  of  Sassafras 
and  Cinnamon  the  following  may  be  mentioned :  A  CINNEOL- 
containing  oil  is  found  in  Cinnamomum  Oliveri  of  Australia, 
Umbellularia  calif ornlca  of  Western  North  America  and  Laurus 
nobilis  the  noble  laurel  of  the  Mediterranean  and  Mexico.  A  BOR- 
NEOL-containing  oil  is  obtained  from  the  root  of  Dicypellium 
caryophyllatum  of  Guiana,  the  wood  of  which  is  known  in 
Cayenne  as  rose-wood.  An  oil  containing  a  notable  amount  of 
METHYL  SALICYLATE  is  obtained  from  the  spice-bush  (Lindera 
Benzoin)  of  the  United  States. 


CLASSIFICATION  OF  ANGIOSPERMS. 


545 


FIG.  304.  Cutting  cinnamon  in  Ceylon.  Cinnamomum  zeylanicum  is  a  native  of  the 
forests  of  Ceylon  and  is  extensively  cultivated,  not  only  on  the  western  coast  of  that  island 
but  in  other  countries  of  tropical  Asia.  The  manner  of  cultivation  is  such  that  a  number  of 
stems  are  allowed  to  grow  from  a  single  root.  When  of  sufficient  height  these  are  cut  down 
and  the  smaller  branches  removed,  as  shown  in  the  illustration.  The  bark  is  then  separated 
from  the  thicker  portion  of  the  stems,  gathered  into  bundles  and  placed  under  mats  until 
a  slight  fermentation  takes  place.  After  the  corky  layer  is  removed  the  product  is  ready 
for  the  market. — Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

Cinnamomum  Camphora,  or  the  camphor  tree,  is  indigenous  to 
China,  Japan  and  Formosa,  and  is  now  cultivated  in  many  warm 
35 


546  A  TEXT-BOOK  OF  BOTANY. 

countries  as  a  shade  and  ornamental  tree,  growing  very  well  in 
Southern  California  and  the  Southeastern  States.  All  parts  of 
the  tree  contain  a  volatile  oil  which  on  oxidation  yields  camphor, 
which  latter  is  obtained  on  distillation  and  sublimation.  Camphor 
of  poor  quality  is  obtained  from  C.  Parthenoxylon  of  Burmah, 
Malaya  and  China,  and  C.  glandulifermn  of  the  Himalayas.  Cam- 
phor is  also  a  constituent  of  other  ethereal  oils  of  this  same 
family,  as  the  Massoy  bark  oil  obtained  from  the  root  bark  of 
C.  zeylanicum  and  C.  Burnianni  of  Java. 

A  EUGENOL-containing  volatile  oil  is  obtained  from  Ravensara 
ar&matica  of  Madagascar,  and  Machilus  Thunbergii  of  Japan. 
Eugenol  is  also  found  in  oil  of  laurel  leaves  (L.  nobilis),  Massoy 
bark  oil,  the  oil  of  the  leaves  of  Ceylon  cinnamon,  and  the  oils 
obtained  from  Cinnamomum  Culilawan  of  the  Malay  Peninsula 
and  China,  and  C.  Wightii  of  East  India,  and  possibly  is  also 
found  in  Dicypellium  caryophyllatum. 

The  wood  and  the  bark  of  Nectandra  or  Beeberu  (Nectandra 
Rodicei)  of  Guiana  and  Brazil  contain  several  alkaloids,  one  of 
which  is  known  as  beeberine  and  is  supposed  to  be  identical  with 
the  alkaloids  in  Buxus  sempervirens  (Earn.  Buxacese)  ;  pelosine 
found  in  Pareira ;  and  paricine  found  in  the  bark  of  the  cultivated 
cinchonas  of  Java.  Coto  bark,  which  is  used  in  medicine,  is 
obtained  from  an  unknown  tree  in  Northern  Bolivia  belonging  to 
this  family.  The  bark  contains  a  volatile  oil  having  a  pungent 
taste,  and  a  volatile  alkaloid. 

Fatty  oils  are  obtained  from  Ravensara  aromatica  of  Mada- 
gascar, Litsea  glauca  of  Japan  and  other  species  of  Litsea  found 
growing  in  Cochin  China  and  India.  A  red  sap  with  a  very  fetid 
odor  is  obtained  from  Ocotea  fattens  of  tropical  and  sub-tropical 
America,  and  the  stink-wood  of  South  Africa  (0.  bullata). 

XIII.  ORDER  RHCEADALES  OR  PAPAVERALES. 

These  are  mostly  herbaceous,  seldom  woody,  plants.  The 
flowers  are  perfect  and  the  fruit  capsular.  This  order  includes 
two  families  of  importance  medicinally. 

a.  PAPAVERACE^E  OR  POPPY  FAMILY.— These  are 
herbs  with  a  milky  or  colored  latex. 

Papaver  somniferum  or  opium  poppy  is  an  annual  herb  I  to  2 


CLASSIFICATION  OF  ANGIOSPERMS. 


547 


M.  high.  The  stem  is  sparingly  branched,  with  alternate,  deeply 
lobed,  pubescent,  clasping  (by  a  cordate  base),  dull  green  leaves 
(Fig.  305,  A).  The  flowers  in  the  variety  album,  from  which 
opium  is  obtained,  are  white  or  silver-gray,  and  in  many  cultivated 
varieties  are  large  and  extremely  showy.  The  two  sepals  drop 
away  with  the  expansion  of  the  corolla ;  the  ovary  is  smooth,  more 
or  less  globular  and  subtends  the  radiate  stigma;  the  fruit  is  a 


FIG.  305.  A,  Opium  poppy  (Papaver  somniferum) ;  B,  California  poppy  (Eschs^holt- 
zia  calif  arnica)  showing  flower  (a),  and  capsules  (b,  c),  one  of  which  (c)  is  dehiscent. — After 
Schimper. 

capsule  (Fig.  238),  dehiscing  by  means  of  terminal  pores,  and 
contains  a  large  number  of  extremely  small  white  seeds,  known  as 
MAW-SEED,  and  which  yield  a  fixed  oil  known  as  poppy-oil.  The 
latex  of  this  plant  (Figs.  306,  307)  yields  opium. 

Other  allied  members  of  the  Papaveraceae  possess  narcotic 
properties,  but  the  alkaloid  morphine  has  not  been  isolated  from 
any  of  them,  as  the  California  poppy  (Eschscholtzia  calif orni ca ) 
(Fig.  305,  B)  ;  the  Mexican  poppy  (Argemone  mexicand)  ;  Hy- 
pe coum  procumbent,  and  Fumaria  plicata,  both  of  Southern 


548 


A  TEXT-BOOK  OF  BOTANY. 


Europe.     These  latter  plants  probably  contain  also  the  alkaloid 
protopine  which  is  apparently  identical  with  fumarine. 

Sanguinaria  canadensis  or  bloodroot,  the  rhizome  of  which  is 
official.  The  plant  is  a  small,  herbaceous,  perennial  herb  with  a  red 
latex.  The  rhizome  is  horizontal,  short  and  thick,  and  gives  rise 
to  a  single,  petiolate,  palmately  5-  to  9-lobed  "leaf  and  a  single 
white  flower  with  a  long  peduncle  (Fig.  308).  The  capsule  is 


FlG.  306.  Poppy  fields  in  the  meadows  8  miles  northwest  of  Ping-li,  Shensi,  China, 
showing  the  plants  with  large  terminal  flowers. — Reproduced  by  permission  of  The  Phila- 
delphia Commercial  Museum. 

oblong,  2-valved,  and  contains  a  number  of  smooth  but  crested 
seeds. 

Chelidonium  ma  jus  (celandine)  is  the  source  of  the  herb 
CHELIDONIUM  which  was  formerly  official.  The  plant  is  a  delicate 
branching  herb  about  0.5  M.  high ;  with  alternate,  deeply  pinnati- 
fid  leaves ;  yellow  flowers ;  slender  elongated  capsule  resembling 
that  of  the  mustards,  and  a  yellow  latex  in  every  part.  Celandine 
is  indigenous  to  Europe  and  Asia  and  is  common  in  waste  places 
in  the  United  States.  The  drug  contains  the  following  alkaloids : 


CLASSIFICATION  OF  ANGIOSPERMS. 


549 


FlG.  307.  Poppy  fields  in  Afionkarohissar,  Turkish  Empire.  The  capsules  are  ready 
to  be  incised,  allowing  the  milky  juice  to  exude,  which  is  then  collected  and  constitutes  the 
opium  of  commerce. — Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 


550  A  TEXT-BOOK  OF  BOTANY. 

Chelidonine  (identical  with  stylophorine),  chelerythrine  (which 
is  fluorescent ),  and  protopine  (found  also  in  opium  and  sangui- 
naria).  It  also  contains  a  bitter  neutral  principle  chelidoxanthin 
and  several  organic  acids  (Fig.  309). 

To  this  family  belong  a  number  of  other  plants  which  contain 
principles  similar  to  or  identical  with  those  found  in  Sanguinaria 
and  Chelidonium,  and  of  these  the  following  are  common  in  the 


FIG.  308.     A  group  of  transplanted  bloodroot  plants  (Sanguinaria  canadensis)  show- 
ing i-flowered  scapes,  and  the  palmately  veined  and  lobed  leaves. 

United  States :  Yellow  or  celandine  poppy  (Stylo phorum  diphyl- 
lum)  and  the  Dutchman's  breeches  (Bicuculla  Cucullaria}. 

The  alkaloid  PROTOPINE  (fumarine)  is  found  in  the  following 
plants  of  this  family :  Sanguinaria  canadensis;  Chelidonium 
majus;  Stylo  phorum  diphyllum;  Eschscholtzia  calif  ornica;  Glau- 
cium  corniculatum  of  Middle  Europe;  Bicuculla  Cucullaria;  Ad- 
lumia  fungosa,  the  climbing  fumitory  of  the  United  States  and 
Canada;  Fumaria  officinalis,  the  fumitory  of  Europe,  which  is 
naturalized  in  the  United  States  and  Canada ;  Bocconia  cordata 
of  China  and  Japan,  and  B.  frutescens  of  the  West  Indies,  Mexico 


CLASSIFICATION  OF  ANGIOSPERMS. 


and  Paraguay ;  Dicentra  pusilla  of  Japan  and  several  species  of 
corydalis.  The  tubers  of  squirrel  corn  or  corydalis  (Bicuculla 
canadensis)  contain  the  alkaloidal  corydaline. 


FIG.  309.  Celandine  (Chelidonium  majus),  a  biennial  herb,  with  pinnately  divided 
leaves,  and  terminal  clusters  of  small,  yellow  flowers.  The  plant  has  an  orange-colored 
latex. — After  Brown. 

b.  CRUCIFER^:  OR  MUSTARD  FAMILY.— These  are 
herbaceous  plants  with  characteristic  flowers  and  fruits.  The 
flowers  have  four  deciduous  sepals,  four  petals  which  are  more  or 
less  spreading  and  clawed  at  the  base,  and  six  stamens  which  are 
tetradynamous  (Fig.  280,  B).  The  fruit  is  a  2-celled  silique  or 


552 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  310.     Fruiting  specimens  of  the  two  mustards,  the  one  on  the  left  White  Mustard 
(Brassica  alba),  and  the  one  on  the  right  Black  Mustard  (Brassica  nigra). — After  Newcomb. 


CLASSIFICATION  OF  ANGIOSPERMS.  553 

silicic,  which  varies  in  shape  in  the  different  genera  (Fig.  310). 

Brassica  alba  (white  mustard). — The  plant  is  a  slender, 
branching,  more  or  less  hispid  (bristly  hairy)  annual  or  biennial 
herb  usually  less  than  0.5  M.  high,  with  deeply  pinnatifid  lower 
leaves  and  lanceolate,  dentate  upper  leaves.  The  flowers  are 
yellow,  and  the  silique  is  densely  hispid,  constricted  between  the 
seeds  and  terminated  by  a  long,  flat,  sword-like  beak  (Fig.  310). 
The  seeds  are  official  as  white  mustard  (Sinapis  alba)  but  are 
known  in  commerce  as  yellow  mustard. 

Brassica  nigra  or  black  mustard,  the  seeds  of  which  constitute 
the  official  black  mustard  (Sinapis  nigra),  is  a  larger,  more  branch- 
ing plant  than  Brassica  alba,  being  from  I  to  3  M.  high.  The 
silique  is  erect,  more  cylindrical  and  with  a  slender,  filiform  beak 
(Fig.  310). 

Glucosides  similar  to  those  which  occur  in  BRASSICA  ALBA  and 
BRASSICA  NIGRA  are  also  found  in  other  species  of  BRASSICA, 
as  well  as  in  the  following  related  plants,  but  the  oils  produced 
are  not  identical:  Horseradish  (Roripa  Armoracia),  the  oil  being 
similar  to  volatile  oil  of  mustard;  water  cress  (R.  Nasturtium)  ; 
garden  radish  (Raphanus  sativus)  ;  Sisymbrium  Alliaria  of  Eu- 
rope, and  the  hedge  mustard  (S.  officinale) naturalized  in  the  United 
States;  TURNIP  (Brassica  Rapa)  of  Europe;  field  penny-cress 
(Thlaspi  arvense)  of  Asia  and  found  in  waste  places  in  the 
Eastern  and  Middle  United  States ;  the  narrow  leaved  pepper- 
grass  (Lepidium  ruder  ale)  naturalized  from  Europe ;  scurvy-grass 
(Cochlearia  officinalis)  of  Northern  and  Middle  Europe,  the  herb 
of  which,  known  as  HERBA  COCHLEARIA,  is  used  in  medicine; 
"  HONESTY"  (Lunaria  annua)  common  in  cultivation  on  account 
of  the  ornamental  use  of  the  dry  pods ;  Parrya  macrocarpa  of 
Southern  Europe;  treacle  mustard  (Erysimum  cheiranthoides)  of 
Northern  Europe  and  the  United  States,  and  garlic  mustard  (E. 
Alliaria). 

The  seeds  of  most  of  the  Cruciferae  are  also  rich  in  fixed  oils, 
and  the  commercial  oils  are  obtained  from  the  following  species : 
Wild  mustard  or  charlock  (Brassica  arvensis)  naturalized  in  the 
United  States  from  Europe ;  Hesperis  tristis  of  Southern  Europe ; 
cabbage  (Brassica  oleracea).  An  INDIGO- forming  glucoside  is 
found  in  Isatis  tinctoria  of  Europe  and  /.  indigotica  of  China; 


554  A  TEXT-BOOK  OF  BOTANY. 

Neslia  paniculata  of  Europe  and  the  Orient ;  and  Lepidium  owai- 
hiense  of  the  Hawaiian  Islands.  Shepherd's  purse  (Capsella 
Bursa-pastoris)  contains  an  alkaloid  (bursine)  and  tannin.  The 
leaves  and  roots  of  many  of  the  Cruciferse  are  used  as  garden 
vegetables,  and  some  are  cultivated  as  ornamental  plants.  The 
seeds  of  Lunaria  biennis  (or  "ho-nesty")  contain  an  orange-red 
crystalline  alkaloid,  or  possibly  a  mixture  of  alkaloids. 

c.  There  are  several  other"  families  of  the  Rhoeadales  which 
yield  economic  products.  The  RESEDACE^E  include  the  migno- 
nette (Reseda  odorata),  the  flowers  of  which  yield  a  fragrant  vola- 
tile oil ;  and  R.  Luteola  of  Europe,  which  contains  a  yellow  coloring 
principle  and  also  an  anthelmintic  principle.  The  MORINGACE^ 
comprise  a  single  genus,  Moringa.  The  root  of  M.  oleifera  of 
tropical  and  sub-tropical  countries  contains  a  volatile  oil  resem- 
bling the  volatile  oil  of  mustard,  and  the  stem  yields  an  astringent 
gum  resembling  that  of  Bombax  malabaricum  (Bombaceae). 

XIV.    ORDER  SARRACENIALES. 

This  order  includes  several  families  which  are  of  special  inter- 
est because  of  the  fact  that  the  leaves  are  of  peculiar  construction 
and  adapted  to  the  catching  and  digestion  of  insects  (Fig.  208). 

Probably  all  of  the  plants  of  this  order  produce  proteolytic 
ferments  resembling  those  in  the  pine-apple  and  are  capable  of 
acting  upon  and  digesting  animal  substance.  Some  writers  have 
supposed  that  the  properties  of  these  plants  might  be  due  to  bac- 
teria present  in  the  liquid  contained  in  the  pitchers  of  the  leaves, 
but  there  seems  to  be  no  question  that  a  distinct  enzyme  resem- 
bling trypsin  is  formed  in  those  plants  which  have  been  studied. 

(a)  The  genus  Sarracenia  of  the  family  SARRACENIACE^E  or 
pitcher-plant  family,  is  represented  in  the  United  States  by  a 
number  of  species.  The  rhizome  of  Sarracenia  purpurea  (Fig. 
311)  contains  several  alkaloids,  one  of  which,  sarracenine,  seems 
to  have  some  resemblance  to  veratrine.  (b)  The  DROSERACE^:  or 
sundew  family  includes  the  Droseras  or  sundew  plants  and  Dioncea 
muscipula,  the  Venus's  flytrap  o-f  North  Carolina  (Fig.  209).  A 
number  of  species  of  Drosera  contain  a  red  coloring  principle 
similar  to  that  isolated  from  the  rhizomes  of  D.  Whittakern  of 
Australia  and  is  a  derivative  of  methylnaphthoquinone.  Citric 


CLASSIFICATION  OF  ANGIOSPERMS. 


555 


FIG.  311.  Pitcher  Plant  (Sarracenia  pur  pur  ea).  The  plant  grows  in  peat  bogs,  and 
the  pitcher-shaped  leaves  are  usually  half  filled  with  water  and  serve  as  a  trap  for  insects, 
which  are  finally  digested  and  furnish  the  plant  with  nitrogenous  food.  The  flowers  are 
single  on  a  naked  scape  and  of  a  deep  purple  color,  the  petals  being  arched  over  the  style. 
Many  species  of  Sarracenia  are  prized  by  horticulturists  because  of  their  odd  trumpet- 
shaped  leaves. — After  Troth. 

acid  has  been  found  in  D.  longifolia,  a  sundew  common  in  the 
•United  States  as  well  as  in  Europe  and  Asia,  (c)  The  family 
•NEPENTHACE^E  contains  the  single  genus  Nepenthes,  several  spe- 


556  A  TEXT-BOOK  OF  BOTANY. 

cies  of  which  are  extensively  cultivated  in  greenhouses.  The 
leaves  and  roots  of  N.  Boschiana  of  Borneo  contain  an  astringent 
principle. 

XV.    ORDER   ROSALES. 

The  plants  range  from  herbs  to  shrubs  and  trees  and  have 
complete  flowers  which  are  mostly  perigynous.  The  carpels  are 
solitary,  or  several  either  distinct  or  united. 

a.  PODOSTEMACE^E   OR   RIVER-WEED   FAMILY.— 
/The  plants  are  aquatic  and  more  or  less  alga-like,  and  are  repre- 
sented in  the  United  States  by  the  river-weed  (Podostemon  Cerato- 
phyllum),  which  is  a  densely  tufted  plant  found  in  running  water 
attached  to  stones.    The  ash  of  these  plants  contains  a  consider- 
able amount  of  sodium  chloride,  the  ash  of  M  our  era  Weddelliana 
of  Brazil  containing  50  per  cent,  of  salt  and  being  used  as  a  source 
of  table  salt. 

b.  CRASSULACE^E  OR  ORPINE  FAMILY.— The  plants 
are  chiefly  succulent  herbs  and  represented  by  such  plants   as 
houseleek   (Sempervivum  tectorum),  which  is  cultivated  largely 
as  an  ornamental  plant,  and  the  common  sedums,  of  which  there 
are  numerous  species  in  temperate  regions.     The  common  mossy 
stonecrop  or  wall-pepper  (Sedum  acre}  naturalized  in  the  North- 
ern United  States  contains  a  ferment  capable  of  dissolving  the 
membrane  formed  in  diphtheria  and  croup  ;  Sempervivum  balsami- 
ferum  of  the  Canary  Islands  contains  a  substance  resembling  the 
viscine  found  in  certain  Loranthacese.    Ditch  or  Virginia  stonecrop 
(Penthorum  sedoldes)  contains  tannin. 

c.  SAXIFRAGACE^E  OR  SAXIFRAGE  FAMILY.— The 
plants  are  mostly  found  in  temperate  regions  and  among  the  im- 
portant members  are  mitrewort  (Mitella),  false  mitrewort  (Tia- 
rella  cordifolia),  alum  root  (Heuchera  americana},  golden  saxi- 
frage (Chrysosplenium) ,  grass  of  Parnassus  (Parnassia),  mock 
orange  (Philadelphus  coronarius)  and  the  wild  hydrangea  (Hy- 
drangea arborescens). 

The  plants  are  rich  in  tannin,  as  the  alum  root  of  Eastern  and 
Central  North  America,  which  contains  10  to  20  per  cent,  of 
tannin.  A  glucoside  hydrangin,  a  volatile  oil,  and  possibly  also 
a  saponin  are  found  in  "SEVEN  BARKS"  or  wild  hydrangea  (PL 


CLASSIFICATION  OF  ANGIOSPERMS. 


FIG.  312.  Early  Saxifrage  (Saxifraga  virginiensis),  a  perennial  herb  with  a  whorl  of 
root  leaves  from  which  arise  the  flower  scapes  bearing  open  and  loosely  panicled  cymes. 
It  grows  in  the  clefts  of  rocks,  and  the  name  is  derived  from  the  Latin,  meaning  to  break 
a  rock.  No  doubt  because  of  its  habit,  medicinal  virtues  were  earlier  ascribed  to  it,  and  it 
was  used  to  cure  stone  in  the  bladder. — After  Troth. 


arborescens)  ;  a  glucoside  is  also  found  in  the  root  of  garden 
hydrangea  (H.  paniculata  grandiflora) . 

In  this  family  are  also  included  the  gooseberries  (Fig.  245) 


558  A  TEXT-BOOK  OF  BOTANY. 

and  currants.  The  cultivated  CURRANTS  are  varieties  of  Ribes 
rubrum:  the  cultivated  GOOSEBERRIES  are  varieties  of  R.  Uva- 
crispa.  Both  of  these  plants  are  natives  of  Europe  and  Asia  and 
have  escaped  from  cultivation  in  the  United  States  and  Canada. 
The  fruits  contain  fruit-acids  and  fruit-sugars  and  are  used  in  a 
variety  of  ways.  The  fetid  currant  (Ribes  prostratum)  has  a  very 
fetid  odor  and  it  is  said  that  the  flowers  of  the  buffalo  currant 
(Ribes  aureum)  contain  hydrocyanic  acid. 

e.  HAMAMELIDACE^:  OR  WITCHHAZEL  FAMILY.— 
The  plants  are  shrubs  or  trees  and  are  most  abundant  in  sub- 
tropical countries. 

Hamamelis.  virginiana,  or  witchhazel,  the  leaves  and  bark 
of  which  are  used  in  medicine,  is  a  shrub  which  is  especially 
characterized  by  its  asymmetric,  undulate  leaves  and  by  its  produc- 
ing flowers  in  the  autumn  when  the  leaves  are  falling  and  the 
mature,  but  not  ripe,  capsules  of  the  preceding  year  are  still 
present  (Fig.  313). 

The  forked  branches  of  the  witchhazel,  as  also  the  twigs  of 
the  peach  and  other  plants,  are  used  in  various  parts  of  the 
United  States  for  detecting  the  presence  of  underground  water. 
These  are  operated  somewhat  as  follows :  The  branched  arms 
are  held  by  the  operator  in  a  horizontal  position  and  as  the  operator 
surveys  the  field,  it  is  supposed  the  main  stem  will  dip  in  the 
direction  indicating  either  underground  water,  petroleum,  etc.  It 
is  the  honest  belief  of  the  operators,  that  the  working  of  the  rod 
is  influenced  by  agencies — usually  regarded  as  electrical  currents 
following  underground  springs  of  water — that  are  entirely  inde- 
pendent of  their  own  bodies,  and  many  uneducated  people  have 
implicit  faith  in  their  ability  to  locate  underground  waters  in  this 
way.  However,  it  is  held  by  scientists  that  the  operation  of  the 
divining  rod  is  generally  due  to  the  unconscious  movements  of  the 
body  or  muscles  of  the  hand. 

Liquidambar  styraciflua  or  sweet  gum-tree  of  the  Atlantic 
coast  of  the  United  States  and  Mexico,  is  a  tall  tree  with  charac- 
teristic cork-wings  on  the  branches ;  3-  to  7~lobed,  petiolate,  finely 
serrate  leaves ;  monoecious  flowers,  and  a  spiny,  globular,  capsular 
fruit.  The  tree  yields  a  balsam  allied  to  the  official  styrax 


CLASSIFICATION  OF  ANGIOSPERMS. 


559 


(storax),    which    is    obtained    from    a    very    similar    tree    (L. 
orientalis). 

f.  PLATANACE^:  OR  PLANE  TREE  FAMILY.— This 


FIG.  313.  Branch  of  Witchhazel  (Hamamelis  virginiana)  showing  alternate,  short- 
petiolate  and  pinnate-reticulately  veined  leaves,  having  a  broadly  oval  or  obovate  out- 
line, round,  acute,  or  slightly  acuminate  apex;  slightly  cordate,  inequilateral  base;  and 
undulate  or  sinuous  margin. 

/amily  consists  of  but  one  genus,  Platanus,  of  which  there  are 
7  species.  It  includes  the  sycamore  or  buttonwood  (Platanus 
occidentalis},  one  of  our  largest  trees,  easily  recognized  by  its 


A  TEXT-BOOK  OF  BOTANY. 


mottled  exfoliating  bark.  The  leaves  are  palmately  lobed  and 
within  the  base  of  the  petioles  are  formed  the  winter  buds.  The 
flowers  are  staminate  and  pistillate  heads,  borne  on  separate  ped- 
uncles. The  fruits  are  spherical  heads  about  2  cm.  in  diameter, 
composed  of  numerous  achenes,  and  persist  on  the  trees  throughout 
the  winter.  The  wood  is  not  only  used  for  building  purposes,  but 
also  for  butchers'  blocks. 


FIG.  314.  Cross- pollination  through  the  agency  of  a  bee,  in  flower  of  quince  (Cy- 
donia  vuigaris).  A,  flowering  branch;  B,  flower  showing  bee  extracting  nectar,  and  masses 
of  pollen  adhering  to  its  legs,  some  of  which  will  fall  upon  the  stigmas  of  other  flowers  when 
it  visits  them;  C,  ripe  inferior  fleshy  fruit  (pome)  of  quince. — After  Dodel-Port. 

/.  ROSACES  OR  ROSE  FAMILY.— The  plants  are  herbs, 
shrubs  or  trees  usually  with  alternate,  stipulate,  simple  or  com- 
pound leaves,  and  regular  perfect  flowers  with  or  without  petals, 
and  numerous  stamens  (Fig.  280,  D).  The  fruit  is  a  pome  (Fig. 
314),  drupe  (Fig.  315),  follicle  or  achene  (Fig.  236). 

Prunus  serotina  or  wild  black  cherry  is  a  tree  varying  from 
10  to  30  M.  in  height,  with  a  more  or  less  smooth  bark  marked  by 
prominent  transverse  lenticels,  and  showing  a  tendency  to  peel 
off  in  semicircular  pieces,  which  gives  the  older  bark,  which  is 
more  or  less  black,  a  roughened  appearance.  The  leaves  and  inner 


CLASSIFICATION  OF  ANGIOSPERMS.  561 

bark  have  an  agreeable  aromatic  odor;  the  leaves  are  oval-  or 
oblong-lanceolate,  acute  or  acuminate,  and  serrate,  the  teeth  being 


.'   FIG.  315.     Fruiting  branch  of  wild  black  cherry  (Prunus  serotina). 

glandular ;  the  flowers  are  white  and  in  racemes ;  the  fruit  is  a 
dark  purple  or  blackish,  globular  drupe  (Fig.  315).     The  nearly 
related  species  wild  cherry  or  choke  cherry  (Prunus  virginiana) 
36 


562  A  TEXT-BOOK  OF  BOTANY. 

is  a  shrub  or  small  tree  with  broadly  oval,  acuminate  leaves,  red 
or  nearly  black  drupes,  and  flowers  and  fruits  several  weeks 
earlier  than  P.  serotina. 

Prunus  Amygdalus  is  a  small  tree  resembling  somewhat  the 
peach  tree.  The  leaves,  are  lanceolate,  serrate;  the  flowers  are 
rose-colored,  and  the  fruit  is  a  dehiscent  drupe  in  which  the 
leathery  sarcocarp  separates  from  the  endocarp,  which  latter,  with 
the  seed  which  it  encloses,  constitutes  the  edible  almond  of  the 
market.  The  kernels  of  some  of  the  seeds  are  quite  bitter  (bitter 
almonds),  and  some  are  bland  and  free  from  bitterness.  By  a 
process  of  selection  plants  yielding  the  latter  are  now  extensively 
cultivated  in  sub-tropical  and  warm-temperate  regions,  and  yield 
the  sweet  or  Jordan  almond  of  the  market.  In  Turkestan  some 
of  the  almonds  have  a  smooth  endocarp. 

A  glucosidal  substance  having  the  properties  of  amygdalin  is 
found  in  the  buds,  leaves,  bark  and  seeds,  more  especially  the 
latter,  of  some  members  of  the  following  genera :  Prunus,  Sorbus 
(mountain  ash),  Cotoneaster,  Amelanchier,  and  Eriobotyra  (E. 
japonica  or  Japanese  medlar). 

Prunus  domestica  yields  the  French  plum  or  prune  of  com- 
merce. The  leaves  are  ovate  or  ovate-lanceolate,  dentate,  and 
pubescent  on  the  lower  surface.  The  flowers  are  greenish-white, 
with  a  hairy  peduncle.  The  fruit  is  a  drupe,  with  a  black  or 
bluish-black  epicarp,  a  brownish  sarcocarp,  and  a  hard,  oval, 
smooth  and  flattened  endocarp. 

The  endocarps  of  the  members  ol  me  genus  Prunus  vary  greatly. 
The  endocarp  in  the  apricot  (P.  Armeniaca)  is  quite  smooth,  as  is 
also  that  of  the  cherry  (P.  Cerasus)  ;  in  the  peach  (Prunus  Per- 
sica)  it  is  reticulate.  The  bark  of  Pyrus  Toringo  yields  a  yellow 
coloring  principle  known  in  Japan  as  "  dzaini."  It  also  contains 
a  white,  crystalline  glucoside  (toringin),  and  pyrus-quercitrin,  the 
latter  forming  yellow  needles  and  on  hydrolysis  yields  quercetin 
and  rhamnose.  The  bark  is  also  used  to  adulterate  licorice,  gentian 
and  other  drugs  in  the  powdered  form. 

The  apple  (Pyrus  Mains) ,  the  pear  (Pyrus  communis) ,  and  the 
quince  (Cydonia  vulgaris)  are  inferior  fruits  known  as  pomes, 
the  fleshy  part  developing  from  the  torus  and  persistent  calyx, 
the  core  being  composed  of  the  united  carpels.  The  edible  fruits 


CLASSIFICATION  OF  ANGIOSPERMS.  563 

of  the  Rosaceae  contain  a  number  of  FRUIT-ACIDS,  such  as  malic, 
citric,  tartaric,  and  FRUIT-SUGARS,  as  dextrose  and  levulose.  The 
acids  vary  from  0.20  per  cent,  in  pears  to  1.50  per  cent,  in  plums ; 
and  the  sugars  from  4.48  per  cent,  in  peaches  to  8.26  per  cent, 
in  pears.  The  carbohydrates  mannit  and  sorbit  are  found  in  the 
fruit  of  Prunus  Laurocerasus  of  Europe.  In  the  unripe  fruits 
there  is  more  or  less  tannin  and  also  a  principle  known  as  PECTOSE. 
This  latter  during  the  ripening  of  the  fruit  is  converted  into 
PECTIN,  a  viscid  principle  which  is  further  changed  into  pectic 
and  pectosic  acids,  the  solutions  of  which  gelatinize  on  cooling,  so 
that  these  fruits  are  adapted  to  jelly  making  (see  pp.  243,  255). 

Rubus  nigrobaccus,  or  high  bush-blackberry,  is  a  branching 
shrub  i  to  2  M.  high  with  reddish,  prickly,  erect  or  recurved  stems. 
The  leaves  are  3-  to  5~foliate,  the  leaflets  being  ovate,  coarsely 
and  unequally  serrate,  and  midrib  and  petiolules  with  stout,  re- 
curved prickles.  The  flowers  are  white,  in  terminal  racemes  and 
with  hairy  and  prickly  stalks.  The  fruit  is  broadly  ovoid  and 
consists  of  an  aggregate,  of  drupelets  which  ripen  in  August  and 
September. 

Rubus  villosus  Ait.  (Rubus  canadensis  L.)  or  low-blackberry 
(Northern  dewberry)  is  a  trailing,  shrubby,  prickly  plant  the 
leaves  of  which  are  3-  to  7-foliate,  the  leaflets  being  oval  or  ovate- 
lanceolate,  serrate  and  nearly  smooth.  The  flowers  are  in  racemes 
and  the  fruit  resembles  that  of  R.  nigrobaccus,  but  is  smaller. 

Rubus  cuneifolius  or  sand-blackberry  of  the  Eastern  and 
Southern  States  is  a  small  shrub  less  than  i  M.  high,  much 
branched,  and  with  straight  or  recurved,  stout  prickles.  The 
leaflets  are  ovate  or  cuneate,  and  densely  pubescent,  as  are  also 
the  young  shoots.  The  inflorescence  consists  of  two  to  five  flowers, 
the  petals  of  which  are  white  or  pinkish.  The  fruit  is  oblong,  more 
or  less  cylindrical,  and  sometimes  20  mm.  long. 

Rubus  Idccus  or  the  cultivated  European  red-raspberry  is  a 
shrub  with  a  glaucous,  bristly  stem  and  with  3-  to  7-foliate  leaves. 
The  flowers  are  white  and  the  red  fruit  consists  of  a  cap-like  col- 
lection of  hairy  drupelets  which  is  easily  detached  from  the  non- 
fleshy  receptacle.  The  fruit  is  used  in  the  preparation  of  syrup 
of  raspberry  which  is  used  for  flavoring.  There  are  a  number  of 
varieties  of  this  species  of  raspberry  in  cultivation,  the  fruits  of 


564  A  TEXi-iiOOiv  oF  BO i AIM. 

which  vary  in  color  from  crimson,  brown,  or  yellow  to  nearly 
white.  The  fine  flavored  but  watery  fruit  of  the  wild  red-rasp- 
berry (R.  strigosus)  is  sometimes  substituted  for  the  fruit  of 
Rubus  Idccus  ( Fig.  243 ) . 

Rosa  gallica,  which  yields  the  red  rose-petals,  official  in  a  num- 
ber of  the  pharmacopoeias,  is  a  native  of  Southern  Europe  and 
is  extensively  cultivated. 

Rosa  centifolia,  which  is  now  known  only  in  cultivation,  and 
of  which  there  are  a  large  number  of  varieties,  is  distinguished 
by  its  glandular  leaflets,  and  its  pale  red  or  pink  petals.  The 
cone-like  collection  of  petals  of  the  flower-bud  is  the  part  which  is 
used  in  medicine,  but  it  is  deficient  in  coloring  .principles  and 
fragrance  as  compared  to  Rosa  gallica. 

Rosa  damascena,  the  petals  of  which  yield  the  oil  of  rose  or 
attar  of  rose,  is  extensively  cultivated  in  Bulgaria  and  to  some 
extent  in  France  and  Germany.  It  flowers  very  profusely,  and 
the  yield  of  oil  is  about  0.02  per  cent.  The  oil  consists  of  a  crys- 
tallizable  hydrocarbon  known  as  rose-camphor  which  is  odorless, 
and  a  liquid  portion  consisting  of  geraniol,  1-citronellol,  1-lina- 
lool,  citral,  n-nonyllic  aldehyde  and  phenyl  ethyl  alcohol.  Similar 
oils  are  obtained  from  other  species  of  Rosa  growing  in  Northern 
Africa,  Abyssinia  and  Northern  India,  as  R.  moschata,  and 
R.  sempervirens. 

The  fruits  of  wild  brier  (Rosa  canina)  naturalized  from 
Europe,  as  well  as  of  other  species  of  Rosa  (R.  pomifera  and 
R.  rugosa),  contain  considerable  malic  and  citric  acids  and  fruit- 
sugars,  and  are  made  into  a  confection  by  boiling  with  syrup.  In 
addition  to  the  fruit-ethers  found  in  the  common  edible  fruits 
of  this  family  and  the  volatile  oil  of  rose,  it  should  be  mentioned 
that  oils  containing  salicylic  acid  are  also  present.  A  number  of 
species  of  Spiraea  contain  salicylic  aldehyde  and  methyl  salicylate. 

Quillaja  Saponaria  is  a  large  tree  having  a  thick  bark  and 
hard  wood.  The  leaves  are  oval,  coriaceous,  slightly  dentate  and 
evergreen  (Fig.  316).  The  flowers  are  monoecious  or  dioecious, 
white,  apetalous,  and  axillary  in  groups  of  one  to  four.  The 
ovary  consists  of  4  to  5  carpels  and  on  ripening  forms  a  star-like, 
spreading  group  of  follicles.  The  inner  bark  is  the  part  used  in 
medicine. 


CLASSIFICATION  OF  ANGIOSPERMS. 


565 


A  spurious  quillaja  bark  (Q.  Pocppigii)  differs  from  the 
official  in  being  thinner,  darker  and  in  having  the  surface  covered 
with  a  coarse  network  of  whitish  lines.  Another  bark,  occurring 
in  quilled  pieces,  from  8-15  cm.  long,  and  1-5  cm.  wide,  has  also 
been  found  in  commerce. 

Hagenia  abyssinica  is  an  ornamental  tree  with  7-  to  13-foliate 
leaves.  The  flowers  are  monoecious  and  occur  in  panicles ;  the 
staminate  being  greenish-yellow  and  with  20  stamens ;  and  the 
pistillate  fragrant,  bicarpellary,  and  with  a  reddish  calyx  (Fig. 


PlG.  316.  Soap-bark  tree  (Quillaja  Saponaria):  A,  flowering  branch;  B,  one  of  the 
hermaphrodite  flowers;  C,  the  latter  in  longitudinal  section. — After  Baillon. 

317).     The  fruit  is  a  nutlet.     The  pistillate  flowers  are  official 
under  the  name  of  Cusso. 

Various  species  of  Prunus  yield  GUMS,  as  cherry,  peach, 
apricot,  etc.  MUCILAGE  is  found  in  the  testa  of  certain  seeds,  as 
of  quince.  The  manna  of  Luristan  is  obtained  from  Pyrus  glabra 
of  Persia.  Tannin  and  gallic  acid  are  found  in  TORMENTILLA 
rhizome  which  is  obtained  from  Potentilla  silvestris,  a  perennial 
herb  of  Europe,  and  other  species  of  Potentilla.  The  fruit  of  the 
hawthorn  (Crat&gus  Oxyacantha)  contains  quercitrin.  A  bitter 
principle  and  tannin  are  found  in  Purshia  tridentata  of  the  Rocky 
Mountains.  Phloridzin  is  found  in  the  root  bark  of  a  number  of 
species  of  Pvnts  and  Prunus 


566 


A  TEXT-BOOK  OF  BOTANY. 


7 


PIG.  317.  Hagenia  abyssinica:  A,  branch  showing  a  large  panicle  of  pistillate 
flowers  and  the  stipulate,  compound  leaves;  B,  C,  staminate  flowers;  D,  E,  pistillate 
flowers. — After  Berg  and  Schmidt. 

In  the  genus  Fragaria  to  which  the  strawberry  belongs,  the 
torus  becomes  large  and  fleshy  and  is  the  edible  part  of  the  fruit. 
The  garden  strawberry  (F.  chilocnsis)  has  a  large  fruit,  the 
achenes  being  sunken  in  the  periphery  of  the  torus  (Fig.  242).  In 


CLASSIFICATION  OF  ANGIOSPERMS.  567 

the  wild  strawberries  the  fruit  is  smaller,  usually  somewhat  flesh- 
colored  and  the  achenes  are  either  embedded  in  the  torus  as  in  F. 
virginiana  or  borne  on  the  surface  as  in  F.  vesca.  The  strawberry 
fruit  contains  about  87  per  cent,  of  water;  6  per  cent,  of  cane 
sugar;  5  per  cent,  of  invert  sugar  (a  mixture  of  dextrose  and 
levulose)  ;  I  per  cent,  of  free  fruit-acids;  and  about  2  per  cent, 
of  nitrogenous  substances. 

g.  LEGUMINOS^E  OR  PULSE  FAMILY.— The  plants  are 
herbs,  shrubs,  trees,  or  vines  with  alternate,  stipulate  and  usually 
compound  leaves.  The  flowers  are  complete,  and  the  corolla  is 
either  regular  or  irregular;  the  stamens  are  usually  united,  and 
the  pistil  is  simple  and  free,  becoming  in  fruit  a  legume.  The 
plants  are  widely  distributed,  many  of  them  being  found  in  the 
Tropics.  Three  principal  sub-groups,  which  have  been  ranked 
as  families  by  some  botanists,  are  recognized. 

1.  PAPILIONAT.E. — Those  species  with  papilionaceous  flowers 
are  separated  into  a  group  called  the  Papilidnatae.    This  sub-group 
has  a  number  of  representatives  in  the  United  States,  as  clover, 
locust,  and  Baptisia  (Fig.  280,  L). 

2.  CESALPINIOIDE.E  include  the  sennas  and  have  flowers  which 
are  nearly  regular,  or  imperfectly,  or  not  at  all  papilionaceous. 

3.  The  MIMOSOIDE^E  include  the  acacias  and  have  flowers  that 
are  regular. 

Cassia  acutifolia  is  a  small  shrub  with  leaves  that  are  8-  to 
i o- foliate.  The  leaflets  are  official  as  Alexandria  or  Tripoli  senna  ; 
the  flowers  are  yellowish  and  in  axillary  racemes;  the  fruit  is  a 
smooth,  flat,  dehiscent  pod,  with  6  to  8  seeds. 

Cassia  angustifolia  is  a  shrub  which  is  cultivated  in  Southern 
India  and  resembles  Cassia  acutifolia.  The  leaflets  which  consti- 
tute India  senna  or  Tinnevelly  senna  are  longer  and  narrow-lanceo- 
late, and  the  pods  are  longer,  and  slightly  crescent-shaped,  as 
compared  to  those  of  C.  acutifolia. 

Cassia  Fistula  or  purging  cassia,  the  pods  of  which  are  used 
in  medicine,  is  a  tree  about  15  M.  high.  The  leaves  are  10  to  12- 
foliate ;  the  flowers  golden-yellow  and  in  racemes ;  and  the  fruit 
is  a  very  long,  cylindrical,  indehiscent  legume.  The  leaves  of 
quite  a  number  of  species  of  Cassia  are  used  in  medicine  and  the 


568 


A  TEXT-BOOK  OF  BOTANY. 


following  are  the  source  of  FOLIA  MALABATHRI  :  C.  Tamala  of 
Assam  and  C.  javanica. 

Glycyrrhiza  glabra  is  a  perennial  herb,  with  8-  to  14- foliate 


FIG.  318.     Spanish  licorice  (Glycyrrhiza  glabra)  plant  grown  from  a  cutting 
by  the  late  Henry  N.  Rittenhouse  of  Philadelphia. 

leaves  (Fig.  318),  the  leaflets  being  glandular  in  the  variety 
glandulifcra;  the  flowers  have  a  violet-colored,  papilionaceous 
corolla,  and  the  fruit  is  a  flat,  dehiscent  legume.  The  rhizome  and 
roots  are  the  parts  used  in  medicine. 


CLASSIFICATION  OF  ANGIOSPERMS.  569 

Cytisus  scoparius  or  green  or  Scotch  broom  is  a  shrub  nat- 
uralized from  Europe.  The  branches  are  numerous,  slender,  erect 
and  grow  close  together,  adapting  them  for  use  as  brooms.  The 
tops  are  used  in  medicine. 

Tamarindus  indica  is  a  tree  attaining  a  height  of  25  M.  The 
leaves  are  pinnately  compound,  having  numerous  sessile,  entire, 


FIG.  319.  Tragacanth  plant  (Astragalus  gummifer)'.  A,  flowering  branch;  B, 
modified,  thorn-like  leaf  with  stipules  at  the  base;  C,  irregular  (bilateral)  flower;  D,  legume 
of  A.  arislatus, — After  Taubert. 

oblong  leaflets ;  the  flowers  are  in  terminal  racemes  and  the  petals 
are  yellow  with  reddish  veins ;  the  fruit  is  a  curved,  indehiscent 
legume  which  has  a  thin  epicarp  and  a  pulpy  sarcocarp  with 
numerous  fibers,  and  contains  a  number  of  flat,  quadrangular 
seeds.  The  pulp  is  the  part  used  in  medicine  as  a  laxative  and 
refrigerant. 

Astragalus  gummifer  is  a  tomentose  shrub  less  than  I  M. 
high.  The  leaves  are  pinnately  compound,  the  leaflets  being  narrow 


570  A  TEXT-BOOK  OF  BOTANY. 

and  elliptical ;  the  flowers  are  pale  yellow,  sessile  and  axillary ; 
the  fruit  is  a  small,  somewhat  cylindrical,  hairy  pod  or  legume. 
The  gummy  exudation  constitutes  the  Tragacanth  of  commerce. 

Acacia  Senegal,  which  yields  gum  Arabic  or  acacia  gum,  is 
a  small  tree  with  bipinnate  leaves  which  are  subtended  by  curved 
spines ;  the  flowers  are  yellow  and  in  dense  spikes ;  the  fruit  is  a 
broad  pod  containing  five  or  six  seeds. 

Acacia  Catechu  is  a  small  tree  which  resembles  Acacia  Senegal 
and  furnishes  Black  Catechu.  ' 


Km 


FIG.  320.  Acacia  Senegal:  A,  flowering  branch:  B,  a  single  flower  showing  numerous 
stamens;  C,  part  of  legume  showing  attachment  of  seeds;  D,  E,  sections  of  seeds. — 
Alter  Taubert. 

Pterocarpus  Marsnpium  is  a  fine  timber  tree  with  spreading 
branches.  The  leaves  are  5-  to  7-foliate,  the  leaflets  being  cori- 
aceous, obovate,  and  emarginate ;  the  flowers  are  pale  yellow,  and 
the  fruit  is  an  indehiscent,  orbicular  pod  with  a  single  reniform 
seed.  The  official  Kino  is  prepared  from  the  juice. 

The  trees  yielding  kino  are  under  State  control  in  Madras. 
According  to  v.  Hohnel  the  kino  is  present  in  special  cells  in  the 
bark,  which  are  arranged  in  radial  rows  in  the  region  of  the  lep- 
tome.  The  cells  are  from  50  to  ioo/x  wide  and  from  100  to 


CLASSIFICATION  OF  ANGIOSPERMS.  571 

500  fj,  long,  the  walls  consisting  of  cellulose.  The  term  "  kino  " 
is  applied  to  the  red  astringent  juices  obtained  from  a  number  of 
plants.  "  AMERICAN  KINO  "  is  a  synonym  sometimes  applied  to 
the  extract  of  Geranium  maculatum  (Fam.  Geraniacese). 

Pterocarpus  santalinus  is  a  small  tree  with  trifoliate  leaves, 
and  flowers  and  fruits  resembling  those  of  P.  Marsupiuin.  The 
heart-wood  is  official. 

Hccmatoxylon  campechianum  is  a  small  tree  with  irregular 
spinous  branches.  The  leaves  are  8-  to  lo-foliate,  the  leaflets  being 
sessile  and  obcordate.  The  flowers  are  fragrant,  have  a  purple 
calyx  and  yellow  corolla,  and  are  in  racemes.  The  fruit  is  a 
slender,  lanceolate,  flat  pod,  which  dehisces  laterally  instead  of 
along  the  sutures.  The  heart-wood  of  this  tree  constitutes  the 
commercial  Logwood,  of  which  about  200,000  pounds  are  con- 
sumed annually,  its  chief  use  being  as  a  dye-wood. 

Krameria  triandra  is  a  shrub  with  a  few,  simple,  ovate-lanceo^ 
late,  sessile,  silver-white,  glistening  leaves.  The  flowers  are  com- 
plete, having  two  purple  petals  and  three  stamens.  The  fruit  is  a 
i-seeded,  globular,  prickly,  indehiscent  pod.  K.  Ixina,  found 
growing  from  Mexico  to  Northern  South  America,  and  K.  argen- 
tea  of  Northern  Brazil,  are  distinguished  by  having  flowers  with 
three  petals  and  four  stamens.  The  root  is  the  part  used  in 
medicine. 

Copaiba  Langsdorffii  is  a  small  tree  found  growing  in  Brazil. 
The  leaves  are  6-  to  10- foliate,  the  leaflets  being  ovate-lanceolate, 
glabrous,  coriaceous,  and  glandular  punctate.  The  flowers  are 
apetalous,  and  the  fruit  is  an  ellipsoidal,  coriaceous,  2-valved  pod 
having  a  single  glandular  seed  with  an  arillus.  An  oleo-resin 
collects  in  longitudinal  cavities  in  the  trunk  of  the  tree,  often 
amounting  to  many  liters,  and  sometimes  the  pressure  thus  pro- 
duced is  sufficient  to  burst  the  trunk  in  places.  The  oleo-resin  is 
official  as  COPAIBA.  The  latter  consists  of  30  to  75  per  cent,  of  a 
volatile  oil  from  which  the  sesquiterpene  caryophyllene  has  been 
isolated ;  a  bitter  acrid  resin  and  a  bitter  principle.  A  similar  prod- 
uct is  obtained  from  a  number  of  other  species  of  Copaiba  growing 
in  South  America,  as  well  as  C.  copallifera  of  Western  Africa,  and 
Hardwickia  Mannii  of  tropical  Africa,  and  H.  pinnata  of  India. 

An  oleo-resin  known  by  the  natives  in  the  province  of  Velasco 


572  A  TEXT-BOOK  OF  BOTANY. 

in  Bolivia  as  "  Copaiba  "  is  obtained  from  Copaiba  paupera.  It 
is  thick,  like  Maracaibo  balsam,  but  lighter  in  color  and  resembles 
in  odor  and  taste  true  copaiba.  It  is  distinguished  from  the  other 
specimens  of  American  copaiba  by  its  dextro- rotation  [a]D  -f-  36°. 
On  the  addition  of  one  to  two  volumes  of  petroleum  ether  it  forms 
a  clear  solution,  giving  a  white  precipitate  on  the  addition  of 
more  ether. 

Toluifera  Balsamum  is  a  tree  about  25  M.  high,  with  a  straight 
trunk,  on  which  the  branches  first  appear  at  a  height  of  from 
15  to  20  M.,  and  is  found  growing  in  Northern  South  America. 
The  leaves  are  compound  and  with  seven  to  eleven  alternate, 
oblong,  acuminate,  glandular-punctate  leaflets;  the  flowers  are 
white  and  in  simple  axillary  racemes ;  the  fruit  is  a  winged,  inde- 
hiscent,  I -seeded  legume.  The  plants  yield  a  balsam  ( official  in 
all  the  pharmacopoeias  and  known  as  BALSAM  OF  TOLU)  which 
occurs  in  schizogenous  cavities  in  the  bark  of  young  twigs,  and 
is  obtained  by  incising  the  bark,  it  being  usually  collected  in  gourds. 
The  balsam  consists  of  75  to  80  per  cent,  of  resin,  which  is  a 
compound  of  tolu-resinotannol,  cinnamic  and  benzoic  acids ;  18  to 
20  per  cent,  of  free  cinnamic  acid ;  0.2  to  I  per  cent,  of  a  volatile 
oil;  and  0.5  per  cent,  of  vanillin.  A  good  tolu  balsam  is  also 
obtained  from  T.  peruifera  growing  in  the  northeastern  part  o>f 
South  America. 

Toluifera  Pereircc  is  a  tree  about  15  M.  high,  which  has  a 
short  trunk  and  begins  to  branch  at  a  height  of  2  or  3  M.  It 
otherwise  resembles  T.  Balsamum.  It  is  found  over  the  whole  of 
Northern  South  America,  extending  through  Central  America  to 
Mexico,  and  is  cultivated  in  Singapore.  The  balsam,  which  is 
formed  as  a  result  of  injury  to  the  trunk,  consists  chiefly  of  esters 
of  benzoic  and  cinnamic  acids,  some  free  cinnamic  acid,  and  vanil- 
lin. A  very  fragrant  vanilla-like  balsam  is  obtained  from  the  fruit 
of  this  same  plant,  and  in  San  Salvador  it  is  known  as  white  Peru 
balsam  to  distinguish  it  from  the  black  Peru  balsam  obtained 
from  the  trunk. 

Physostigma  venenosum  is  a  woody  climber.  The  leaves  are 
3-  foliate,  the  leaflets  being  ovate -acuminate;  the  flowers  are  violet 
in  color  and  in  axillary  racemes;  the  fruit  is  a  broadly  linear, 
somewhat  flattened,  distinctly  veined,  dehiscent  pod  which  tapers 


CLASSIFICATION  OF  ANGIOSPERMS. 


573 


at  both  ends,  and  usually  contains  two  or  three  seeds.    The  seeds 
are  official  as  Physostigma. 


FIG.  321.  Wild  Indigo  (Baptisia  tinctoria),  a  perennial  herb  resembling  a  shrub, 
possessing  nearly  sessile,  3-foliate  leaves,  and  having,  at  the  ends  of  the  branches,  loose 
racemes  of  yellow  flowers.  A  pale  blue  coloring  principle  has  been  obtained  from  the  plant 
resembling  indigo,  though  somewhat  inferior. — After  Brown. 

The  blue  coloring  principle  INDIGO  is  mostly  obtained  from 
the  herbs  Indigo f era  tinctoria  and  /.  Anil  which  are  indigenous 


574  A  TEXT-BOOK  OF  BOTANY. 

to,  and  cultivated  in,  tropical  and  sub-tropical  countries.  It  is 
prepared  by  extracting  the  leaves  with  water.  The  glucosidal 
principle  indican  (or  mother-substance  of  indigo  blue)  undergoes 
oxidation  and  the  insoluble  indigo  blue  separates  out.  This  is  the 
commercial  indigo.  A  similar  principle  is  found  in  the  wild  indigo 
(Baptism  tinctoria)  of  the  United  States  and  Canada;  the  leaves 
of  Robinia  Pseud-acacia  of  North  America;  several  species  of 
Psoralea  and  Amorpha,  as  well  as  some  other  Leguminosse.  It  is 
also  found  in  other  families,  as  in  Polygonaceae,  Cruciferse,  Ascle- 
piadacese,  and  Apocynaceae. 

A  yellow  coloring  principle  is  found  in  the  dyer's  broom 
(Genista  tinctoria)  of  Europe  and  Asia  and  naturalized  in  the 
New  England  States.  G.  ovata  of  Europe  yields  a  similar  dye. 

COPAL  RESINS  are  derived  from  a  number  of  the  Leguminosse : 
American  copal  from  Hymen&a  Coubaril  of  the  West  Indies  and 
South  America ;  Brazilian  copal  from  H.  Martiana  of  Rio  Negro ; 
Zanzibar  or  Chakazzi-copal  from  Trachylobium  mossambicense  of 
Western  Africa ;  Sierra  Leone  copal  (yellow  gum,  red  gum)  from 
Copaiba  Guibourtia  of  Sierra  Leone;  Inhambane  copal  from  Co- 
paiba conjugata  and  C.  Gorskiana  of  Singapore,  Jamaica  and 
Australia. 

A  number  of  the  LOCO-WEEDS  containing  principles  poisonous  to 
cattle  belong  to  the  Leguminosae.  The  word  "  loco,"  meaning 
crazy,  is  of  Spanish  origin,  and  is  applied  in  reference  to  the  pecu- 
liar nervous  symptoms  manifested  by  the  affected  animals.  The 
plants  causing  greater  loss  than  all  other  poisonous  plants  com- 
bined and  regarded  as  loco-plants  par  excellence  are  Aragallus 
Lamberti  and  Astragalus  mollissimus.  Of  these  two  Aragallus 
Lamberti,  also  commonly  known  as  rattleweed  or  white  loco,  is  the 
most  poisonous  and  has  a  wide  range,  extending  from  Alaska  on 
the  north  down  through  the  whole  grazing  region  of  the  Great 
Plains,  where  it  is  very  abundant.  Astragalus  mollissimus,  known 
as  purple  loco,  woolly  loco,  or  Texas  loco,  is  more  limited  in  its 
range.  Among  other  plants  causing  heavy  losses  to  stockmen  on 
the  grazing  lands  of  the  Great  Plains  east  of  the  Rocky  Mountains 
may  be  mentioned  the  following :  Zygadenus  elegans  ( Earn.  Lili- 
acese),  especially  dangerous  to  sheep ;  the  larkspurs  or  Delphiniums 
(Earn.  Ranunculaceae),  causing  losses  among  cattle;  and  lupines, 


CLASSIFICATION  OF  ANGIOSPERMS.  575 

causing  losses  especially  among  sheep.  The  water  hemlock 
(Cicuta  maculata,  Fam.  Umbelli ferae)  is  poisonous  to  all  higher 
animals,  including  man.  Among  other  plants  poisonous  to  cattle 
the  following  may  be  mentioned:  California  loco-weed  (Astrag- 
alus Crotalarice) ,  Texas  or  woolly  loco-weed  (A.  mollissimus) , 
rattle-box  (Crotalaria  sagittalis)  found  in  the  Eastern  United 
States  and  Canada.  The  poisonous  action  of  some  of  these  plants 
has  been  ascribed  to  the  presence  of  barium  salts,  although  this 
has  not  been  substantiated  in  all  cases.  Clitoria  glycinoides  of 
Brazil  and  Phaca  ochroleuca  of  Chile  are  poisonous  to  horses 
and  should  probably  be  included  with  the  loco-weeds. 

A  large  number  of  the  plants  belonging  to  the  Leguminosae 
contain  toxic  principles'  and  those  which  have  not  already  been 
considered  might  be  grouped  according  to  the  principles  which 
they  contain. 

1.  ARROW-POISON  group,  including  the  genera  Erythrophlceum, 
Afzelia  and  Pithecolobium. 

2.  FISH-POISON  group,  including  the  genera  Albizzia,  Afzelia, 
Bauhinia,  Barbiera,  Enterolobium,  Leucaena,  Millettia,  Tephrosia, 
Acacia,  Abrus,  Clitoria,  Mundulea,  Derris,  Lonchocarpus,  Pisci- 
dia  (P.  Erythrina  or  Jamaica  dogwood,  which  contains  a  curare- 
like  alkaloid). 

3.  SAPONiN-containing  plants  as  the  genera  Acacia,  Albizzia, 
Entada  (E.  scandens  or  the  sea  bean  of  the  East  and  West  Indies), 
Enterolobium,  Gleditsia  and   Gymnocladus   (G.   dioica  or  Ken- 
tucky coffee-tree  growing  in  the  United  States  and  Canada). 

4.  CvTisiNE-containing  plants ;  the  alkaloid  cytisine  is  found  in 
Laburnum  vulgar e  and  L.  alpinum  growing  wild  in   Southern 
Europe  and  also  cultivated,  and  in  one  or  more  species  of  the 
following    genera :    Anagyris,    Baptisia,     Coronilla,     Crotalaria, 
Genista,  and  Ulex. 

Abrin,  composed  of  a  globulin  and  albumose  and  whose  prop- 
erties are  affected  at  a  temperature  of  50°  C.  or  over,  is  found  in 
the  seeds  of  JEQUIRITY  (Abrus  precatorius)  and  Cassia  hispidula 
of  Mexico;  two  alkaloids  (lupinine  and  lupinidine)  and  a  bitter 
glucoside  (lupinin)  are  found  in  the  white  lupine  (Lupinus  albus) 
of  Europe  and  in  other  species  of  Lupinus  ;  a  glucoside  (wistarin) 
and  a  poisonous  resin  are  found  in  WISTARIA,  species  of  Wisteria, 


576  A  TEXT-BOOK  OF  BOTANY. 

a  common  woody  climber  in  cultivation  as  an  ornamental  plant; 
the  glucoside  ononin  is  found  in  RADIX  ONONIDIS,  the  root 
of  Ononis  spinosa  of  Europe;  the  glandular  hairs  on  the  pods  of 
Mucuna  pruriens  and  M.  urens  growing  in  the  Tropics  of  both 
hemispheres  constitute  the  COWHAGE  of  medicine ;  butyric  acid  is 
found  in  ST.  JOHN'S  BREAD,  the  fruit  of  Ceratonia  Siliqua,  which 
grows  in  European  countries  bordering  the  Mediterranean,  and 
also  in  Eperua  falcata  of  Guiana. 

A  bitter  principle,  bondicine,  known  as  poor  man's  quinine,  is 
found  in  Ccesalpinia  Bonducella  and  other  species  of  Cccsalpinia 
growing  in  Sumatra,  Borneo,  New  Zealand  and  Brazil ;  the  seeds 
of  Phaseolus  lunatus  of  the  East  Indies  contain  a  principle  from 
which  hydrocyanic  acid  is  derived. 

The  seeds  of  many  of  the  plants  belonging  to  the  Leguminosse 
are  rich  in  starch  and  proteins  and  hence  are  used  as  foods.  The 
protein  LEGUMIN  is  characteristic  of  this  family.  The  following 
are  some  of  the  important  food  plants:  the  garden  pea  (Pisum 
sativum),  the  garden  bean  (Phaseolus  vulgaris)  ;  lentil  (Lens 
esculenta),  Japanese  Soy  bean  (Glycine  hispida).  The  peanut 
(Arachis  hypogcea)  indigenous  to  Brazil  and  extensively  culti- 
vated in  most  of  the  Southern  States  and  in  Southern  Europe, 
belongs  to  the  group  of  plants  which  have  geocarpic  fruits,  that 
is,  fruits  which  penetrate  the  soil  during  their  development  and 
ripen  under  ground  (Fig.  231).  In  peanuts  the  starch  is  re- 
placed by  a  fixed  oil  which  is  present  to  the  extent  of  about  45 
per  cent,  and  which  is  an  article  of  commerce.  In  addition  to 
the  seeds  mentioned  those  of  a  number  of  other  plants  as  well 
as  some  fruits,  roots  and  leaves  are  used  as  foods  in  various  parts 
of  the  world,  particularly  in  the  Tropics.  The  plants  of  a  number 
of  species  are  used  as  forage,  as  those  of  clover  (Trifolium)  ; 
some  are  cultivated  as  ornamental  plants,  as  sweet  pea  (Lathyrus 
odoratus),  and  some  yield  valuable  timber,  as  the  locust  (Robinia). 

Soy  Bean'  (Glycine  hispida)  is  an  important  food  plant  and 
forage  crop.  The  plant  is  an  annual  with  trifoliate  hairy  leaves, 
rather  inconspicuous  pale  or  violet-colored  flowers,  and  with  broad 
pods  containing  2  to  5  seeds.  The  seeds  are  more  or  less  com- 
pressed, spherical  or  elliptical  and  vary  in  color  from  whitish- 
or  yellowish-green  to  brownish-black.  The  yield  of  seed  per 


CLASSIFICATION  OF  ANGIOSPERMS.  577 

acre  may  run  as  high  as  40  bushels.  As  a  forage  crop  it  yields 
as  high  as  2  to  3  tons  of  cured  hay  per  acre.  The  seeds  contain 
about  5  per  cent,  of  starch  and  nearly  50  per  cent,  protein  sub- 
stances. The  seeds  are  therefore  very  nutritive  and  are  exten- 
sively used  in  feeding  of  live  stock.  In  Japan  the  seeds  are 
known  as  "  Soy,"  being  derived  from  the  Japanese  word  "  Shoyu," 
in  allusion  to  a  preparation  made  from  the  seeds.  In  Europe  it  is 
also  used  to  a  limited  extent  as  a  food.  In  this  country  it  is  used 
to  some  extent  as  a  food  for  persons  suffering  from  diabetes. 

ALFALFA  or  Lucerne  (Medicago  sativa)  is  one  of  the  most  val- 
uable forage  plants  known  to  man.  It  is  a  perennial  herb  with 
obovate-oblong  leaves,  bluish  purple  flowers  occurring  in 
racemes,  and  twisted  pods.  Alfalfa  is  extensively  cultivated  in 
all  parts  of  the  United  States.  It  is  an  exceptionally  deep-rooted 
leguminous  plant  and  under  the  best  conditions  is  long  lived, 
growing  in  the  arid  lands  of  the  West  as  well  as  in  the  rich  soils 
of  the  East.  In  many  essentials  and  in  feeding  for  stock  alfalfa 
resembles  the  clover.  The  alfalfa  is  relatively  somewhat  richer  in 
digestible  protein  than  the  clover  but  considerably  lower  in  fat. 

VEGETABLE  BEZOARS  are  concretions  formed  in  the  stomachs 
of  ruminating  animals.  They  consist  of  the  hairs  of  crimson 
clover  and  the  awns  of  oats,  barley  and  other  cereal  grains.  They 
are  spherical  in  shape,  of  a  yellowish-brown  color,  with  smooth, 
even  surfaces,  of  a  firm  texture,  and  saturated  with  intestinal 
juices.  The  balls  when  dried  shrink  but  little  and  vary  from  10  to 
12  cm.  in  diameter.  Since  the  introduction  into  the  United  States 
of  crimson  clover  as  a  forage  plant  or  green  manure,  there  have 
been  numerous  deaths  reported  among  horses  and  other  cattle 
due  to  their  eating  crimson  clover,  which  leads  to  the  formation 
of  bezoars  caused  by  the  undigested  hairs  matting  together.  An 
examination  of  these  bezoars  shows  that  the  hairs  of  which  they 
are  composed,  lie  with  the  broken  or  basal  end  toward  the  center 
of  the  ball,  the  sharp  summit  being  directed  toward  the  surface. 

XVI.    ORDER    GERANIALES. 

This  order  includes  a  number  of  families  of  economic  impor- 
tance.    The  sepals  are  mostly  distinct ;  the  stamens  are  few ;  the 
carpels  are  united,  and  the  ovules  are  pendulous  (epitropous). 
37 


578  A  TEXT-BOOK  OF  BOTANY. 

a.  GERANIACE^E  OR  GERANIUM  FAMILY.— The 
plants  are  herbs  with  alternate  or  opposite,  usually  stipulate  leaves, 
regular  and  perfect  flowers,  and  capsular  fruit  ( Fig.  236,  C) . 

Geranium  maculatum  is  a  perennial  herb  (Fig.  322)  with  a 
short,  thick,  horizontal  rhizome,  from  which  arises  a  simple,  some- 


FIG.  322.      Geranium    maculatum    showing    typical    dicotyledonous    flowers 
and  the  s-parted,  reticulately-veined  leaves. 

what  branching,  hairy  stem,  with  3-  to  5-parted,  variously  toothed 
and  cleft,  petiolate  leaves,  those  on  the  upper  part  of  the  stem 
being  opposite;  the  flowers  are  regular  and  5-merous,  occurring 
singly  or  in  twos  in  the  axils  of  the  leaves;  the  petals  are  rose- 
purple  and  hairy  at  the  base ;  the  fruit  is  a  dehiscent  capsule ;  the 


CLASSIFICATION  OF  ANGIOSPERMS.  579 

five  carpels  when  ripe  separate  and  roll  upwards,  remaining 
attached  to  a  central  column  by  means  of  a  slender  carpophore,  the 
individual  carpels  being  in  the  nature  of  achenes.  The  rhizome  is 
the  portion  used  in  medicine. 

The  cultivated  geraniums  belong  to  the  genus  Pelargonium, 
and  some  of  the  species  furnish  oil  of  rose  geranium,  as  P.  odora- 
tissimum,  P.  capitatum  and  P.  Radula,  all  of  which  are  cultivated 
in  France,  Spain,  Germany,  Algiers  and  Reunion  for  the  oil,  which 
is  largely  used  in  perfumery.  The  oil  contains  geraniol,  cit- 
ronellol,  and  various  esters.  The  leaves  of  Pelargonium  peltatum, 
growing  in  certain  parts  of  Africa  and  Australia,  contain  oxalic 
acid  and  acid  oxalates. 

b.  OXALIDACE^:  OR  WOOD-SORREL  FAMILY.— To 
this  family  belongs  the  genus  Oxalis,  some  species  of  which  have 
leaves  that   are  quite   sensitive  to   light  as   well   as   mechanical 
stimuli,  which  applies  especially  to  the  cultivated  forms  of  South 
Africa,  and  to  the  common  wood-sorrel   (Oxalis  Acetosella)   of 
the  United  States  and  Canada,  as  well.    The  leaves  contain  oxalic 
acid  and  acid  oxalates. 

c.  THE  TROP^OLACE^:  OR  NASTURTIUM  FAMILY 
comprises  but  a  single  genus,  Tropaeolum.    Some  species  are  culti- 
vated for  ornamental  purposes  and  are  the  nasturtiums  of  the 
garden.     The  young  shoots  are  succulent  and  taste  like  some  of 
the  cresses,  hence  they  have  received  the  name  "  Indian  cress." 
They  contain  volatile  constituents  resembling  those  of  the  Cruci- 
ferae,  and  in  the  leaves  of  Tropccolum  majus  benzyl  mustard-oil 
is  found.     The  flower-buds  and  young  fruits  of  this  species  are 
used  for  pickling  like  capers. 

d.  LINAGES  OR  FLAX  FAMILY.— The  most  important 
plant  of  this  family  is  the  common  flax  (Linum  usitatissimum) . 
This  is  an  erect,  slightly  branching  annual  herb  with  alternate, 
lanceolate  and  3-nerved  leaves.    The  flowers  are  in  terminal,  leafy 
panicles,  the  pedicels  being  slender,  the  calyx  non-glandular,  and 
the  petals  blue  (Fig.  280,  A).    The  fruit  is  a  lo-locular,  lo-seeded 
capsule.    The  seeds  are  official.    There  are  a  number  of  cultivated 
varieties  and  the  seeds  of  the  var.  hitmile  contain  a  glucoside 
which  yields,  under  the  influence  of  ferments,  hydrocyanic  acid. 
A  cathartic  principle  has  been  found  in  L.  catharticum  growing  in 


A  TEXT-BOOK  OF  BOTANY. 


Europe.  The  bast  fibers  of  Linum  usitatissimum  are  used  in  the 
manufacture  of  linen.  These  fibers  are  distinguished  from  many 
other  vegetable  fibers  in  not  containing  lignin. 

e.  ERYTHROXYLACE^:    OR    COCA    FAMILY.— This 
family  contains  but  two  genera,  one  of  which  is  Erythroxylon. 


FIG.  323.  Flowering  branch  of  Erythroxylon  Ccca  showing  the  parallel  lines  on  either 
side  of  the  midrib,  which  are  not  true  veins,  brt  due  to  an  extra  development  of  hypodermal 
cells  in  this  region. — After  Reiche. 

The  official  coca  leaves  (Fig.  323)  are  obtained  from  Erythroxy- 
lon Coca.  The  plant  is  a  shrub  and  requires  a  very  humid  atmos- 
phere and  a  comparatively  high  elevation.  The  leaves  are 
alternate,  petiolate  and  entire ;  the  flowers  are  white  and  very 
small ;  the  fruit  is  a  reddish  drupe  resembling  that  of  dogwood. 
Coca  leaves  contain  several  alkaloids,  including  cocaine,  cinna- 


CLASSIFICATION  OF  ANGIOSPERMS.  581 

myl-cocaine,  truxilline  and  ecgonine.  Of  these  cocaine  is  the  most 
important,  the  Bolivian  leaves  containing  the  greatest  amount,  or 
0.5  to  i  per  cent. ;  the  other  alkaloids  preponderate  in  the  Peruvian 
leaves,  which  usually  do  not  contain  more  than  one-half  or  two- 
thirds  as  much  cocaine  as  the  Bolivian  leaves ;  the  Java  leaves  also 
contain  benzoyl-pseudotropine ;  in  addition,  coca  leaves  contain  a 
volatile  aromatic  principle ;  and  a  tannin  giving  a  green  color  with 
ferric  salts. 

COCAINE  (benzoyl-methyl-ecgonine)  occurs  in  monoclinic 
prisms.  The  hydrochloride  of  cocaine  with  palladous  chloride 
forms  a  characteristic  crystalline  double  salt  (Fig.  97). 

Other  species  of  Erythroxylon  also  yield  useful  products.  An 
aromatic  oil  is  found  in  the  wood  of  E.  monogynum  of  Ceylon 
and  India,  and  the  wood  is  known  as  "  bastard  cedar  "  or  "  bastard 
santal."  A  brownish-red  coloring  principle  is  found  in  the  red- 
wood (E.  cerolatum)  of  Jamaica  and  in  E.  suberosum  and  E. 
tortuosum.  Purgative  and  anthelmintic  principles  are  found  in 
some  species  of  this  genus. 

/.  ZYGOPHYLLACE;E  OR  CALTROP  FAMILY.— The 

plants  are  mostly  herbs  and  shrubs  which  are  widely  distributed 
in  warm-tropical  regions.  The  leaves  are  mostly  opposite,  pin- 
nate and  stipulate.  The  genus  Guaiacum  is  of  interest  on  account 
of  the  wood  containing  considerable  resin,  which  is  used  in 
medicine. 

Guaiacum  officinale  is  a  small  tree  with  4-  to  6- foliate  leaves, 
the  leaflets  being  ovate,  entire  and  sessile;  the  flowers  are  large, 
blue,  and  in  axillary  clusters ;  and  the  fruit  is  a  2-valved  capsule 
(Fig.  324).  G.  sanctum  is  a  tree  resembling  G.  officinale,  but  is 
distinguished  by  having  leaves  which  are  8-foliate  and  with 
smaller  leaflets,  and  a  4-  to  5-valved  capsule.  The  resin  of  both 
species  is  official. 

A  resin  having  an  odor  resembling  that  of  creosote  occurs  in 
the  CREOSOTE  BUSH  (Covilleo,  tridentata)  of  Mexico  and  Texas. 

The  juice  of  Peganum  Harmala  contains  a  yellow  coloring 
principle  used  in  dyeing.  A  number  of  the  plants  of  this  family 
contain  powerful  poisonous  principles. 

g.  RUTACE^E  OR  RUE  FAMILY.— The  plants  are  shrubs 
or  trees,  seldom  herbs,  with  lysigenous  oil-secretion  cells.  The 


582 


A  TEXT-BOOK  OF  BOTANY. 


leaves  are  usually  alternate,  simple  or  compound  and  glandular- 
punctate  (Fig.  280,  C). 

Zanthoxylum  americanum  or  northern  prickly  ash  is  a  shrub 
or  small  tree  with  5-  to  n -compound  leaves,  the  leaflets  being 
ovate  and  nearly  sessile;  the  flowers  are  dioecious,  greenish,  and 
in  axillary  cymes  ;  the  fruit  is  a  black,  2-valved  capsule.  Z.  Clava- 
Herculis  or  the  southern  prickly  ash  is  a  very  prickly  shrub,  which 


FIG.  324.  Guaiacum  offlcinale:  A,  flowering  and  fruiting  branch;  B,  gynaecium  in 
longitudinal  section  showing  the  pendulous  ovules;  C,  a  seed;  D,  E,  the  fruit  in  longitudinal 
and  transverse  sections. — After  Berg  and  Schmidt. 

is  characterized  by  having  cork-wings  on  the  bark.  The  leaves 
are  5-  to  17-foliate,  the  leaflets  being  ovate  and  crenulate;  the 
flowers  are  in  terminal  racemes  and  have  a  calyx  of  4  or  5  sepals, 
the  calyx  being  wanting  in  Z.  americanum.  The  bark  of  these 
two  species  is  official. 

PILOCARPUS. — To  this  genus  belong  a  number  of  species  which 
are  shrubs  or  small  trees  and  indigenous  to  tropical  America. 
The  leaves  are  mostly  pinnately-compound,  the  leaflets  being 
coriaceous  and  entire;  the  flowers  are  small,  greenish  and  in 
axillary  or  terminal  racemes;  the  fruit  is  a  i-seeded,  2-valved 


CLASSIFICATION  OF  ANGIOSPERMS.  583 

capsule.  The  leaves  of  three  species  are  official  as  Pilocarpus 
or  Jaborandi. 

BAROSMA. — The  buchu  leaves  of  medicine  are  obtained  from 
several  species  of  Barosma  (see  Vol.  II).  The  plants  are  branch- 
ing shrubs  with  opposite,  coriaceous,  serrate  or  dentate  leaves 
with  glandular  margins  ;  the  flowers  are  white  or  reddish  and  occur, 
i  to  3,  in  the  axils  of  the  leaves ;  the  fruit  is  a  5-valved  capsule. 
The  leaves  contain  a  volatile  oil,  one  of  the  constituents  of  which 
is  diosphenol. 

CITRUS.: — The  fruits  of  a  number  of  species  of  this  genus  are 
edible,  and  the  plants  are  also  valued  for  their  volatile  oils.  They 
are  aromatic,  glandular,  mostly  thorny  shrubs  or  small  trees 
indigenous  to  tropical  and  sub-tropical  Asia,  and  now  extensively 
cultivated  in  tropical,  sub-tropical  and  warm-temperate  regions. 
The  leaves  are  more  or  less  winged-petiolate,  glaucous,  coria- 
ceous, mainly  unifoliate  (or  trifoliate)  ;  the  flowers  are  complete, 
with  a  3-  to  6-toothed  gamosepalous  calyx,  and  4  to  8  glandular 
petals ;  the  stamens  are  20  to  60,  in  groups  of  I  to  9 ;  the  ovary 
is  subtended  by  a  cushion-shaped  disk,  and  the  fruit  is  a  spher- 
ical, oblong  or  pear-shaped  berry,  having  a  coriaceous  pericarp 
with  numerous  lysigenous  oil-glands,  a  juicy  pulp  made  up  of 
peculiar  hair-structures  which  arise  from  the  endocarp,  and  in 
which  are  embedded  white  polyembryonic  seeds  (Fig.  280,  C). 

Botanists  have  divided  this  genus  into  two  sub-groups-:  (a) 
the  Pseudo-y£gle  group  is  represented  by  the  trifoliate  orange 
(Citrus  trifoliata),  cultivated  widely  in  the  United  States  as  a 
hedge.  The  leaves  are  trifoliate  and  deciduous,  the  petals  spatu- 
late  and  the  ovary  and  disk  hairy,  (b)  In  the  Eucitrus  group  the 
leaves  are  unifoliate  and  evergreen,  the  petals  oblong,  and  the 
ovary  and  disk  glabrous.  This  latter  group  includes  the  two 
species  which  yield  most  of  the  edible  Citrus  fruits. 

Citrus  Aurantium  includes  a  number  of  sub-species  and  varie- 
ties. The  plants  are  small  trees  with  leaves  having  winged 
petioles;  fragrant,  white  flowers;  and  a  more  or  less  globular 
fruit.  The  SWEET  ORANGE  (Malta,  Portugal)  is  derived  from  the 
sub-species  sinensis.  The  BITTER  ORANGE  (Seville,  Curasao) 
is  derived  from  the  sub-species  amara.  The  flowers  of  both  the 
Sweet  and  Bitter  Orange  tree  contain  a  volatile  oil  known  as  OIL 


584  A  TEXT-BOOK  OF  BOTANY. 

OF  NEROLI,  and  composed  of  limonene,  geraniol,  linalool,  etc.  The 
oil  from  the  rind  of  the  fruit  is  known  as  OIL  OF  ORANGE  PEEL,  and 
is  obtained  chiefly  from  Italy  and  Sicily.  It  is  composed  of 
limonene,  citral,  citronellol,  etc.  The  oil  from  the  Bitter  Orange 
peel  has  a  superior  flavor  and  is  known  as  BIGARADIA  OIL.  The 
Bergamot  Orange  is  the  fruit  of  the  sub-species  Bergamia,  culti- 
vated in  Europe,  but  only  rarely  in  the  United  States.  The  oil  of 
the  rind  of  the  fruit  is  known  as  BERGAMOT  OIL  and  consists 
largely  of  linalyl  acetate.  In  the  group  of  MANDARIN  or  Kid- 
glove  orange  (Citrus  nobilis)  the  fruit  is  compressed,  spherical, 
5—6  cm.  in  diameter  and  with  an  orange-yellow,  loose  and  easily 
removable  rind.  The  SHADDOCK  or  grape-fruit  is  derived  from 
the  sub-species  sinensis  var.  decumana,  a  tree  indigenous  to 
the  Malay  Archipelago  and  extensively  cultivated  in  India,  Flor- 
ida, California  and  elsewhere.  The  fruits  are  quite  large,  some- 
times weighing  several  kilograms,  and  those  which  are  round  are 
the  most  valuable  commercially,  being  known  as  Pomelos  or 
GRAPE-FRUITS.  The  BLOOD  ORANGE  is  the  fruit  of  the  sub-species 
sinensis  var.  sanguined.  The  OTAHEITE  ORANGE,  which  is  ex- 
tensively cultivated  as  a  dwarf  pot  plant  and  the  foliage  and 
flowers  of  which  resemble  those  of  lemon,  is  probably  a  variety  of 
the  sub-species  sinensis,  or  it  may  be  a  hybrid  of  lemon  and  orange. 
The  NAVEL  ORANGE  is  a  sweet  orange  in  which  an  additional 
compound  ovary  is  developed  within  the  fruit. 

LEMON  and  LIME  fruits  are  derived  from  sub-species  of  Citrus 
Medico,,  which  are  mostly  shrubs  with  simple,  petiolate  leaves, 
reddish  twigs  and  flowers,  and  more  or  less  ellipsoidal  fruits. 
Lemons  are  derived  from  the  sub-species  Limonum.  The  rind  of 
the  fruit  yields  the  OIL  OF  LEMON,  which  consists  of  limonene, 
citral,  etc.  Most  of  the  commercial  article  comes  from  Sicily  and 
Calabria.  Lime  fruits  or  limes  are  derived  from  the  sub-species 
acida,  a  shrub  cultivated  in  the  West  Indies  and  Florida.  The 
CITRON  fruit,  the  rind  of  which  is  used  in  the  making  of  preserves 
and  confections,  is  derived  from  the  sub-species  genuina.  The 
fruit  is  large  and  lemon-like  but  with  a  thick  rind,  the  plant  being 
cultivated  to  some  extent  in  Florida  and  California. 

The  KUMQUAT  ORANGE  is  obtained  from  Citrus  japonica,  a 
thornless  tree  with  spreading  dwarf  habit  extensively  cultivated 


CLASSIFICATION  OF  ANGIOSPERMS.  585 

in  China  and  Japan  and  very  hardy  even  in  Northern  Florida. 
The  fruit  is  round  or  oblong,  from  3  to  5  cm.  long  and  2  to  3  cm. 
in  diameter,  and  of  an  orange-yellow  color;  the  rind  is  sweet, 
while  the  pulp  is  acid,  and  usually  free  from  seeds,  although  from 
i  to  4  slightly  beaked  seeds  may  be  present. 

The  inner  white  portion  of  the  rind  of  the  Citrus  fruits  con- 
tains a  crystalline,  tasteless  glucoside  known  as  hesperidin  (see 
pp.  151-154).  Those  which  are  bitter  contain  in  addition  several 
bitter  glucosides,  namely,  aurantiamarin  and  naringin.  (See 
Aurantii  Amari  Cortex,  and  Aurantii  Dulcis  Cortex,  in  Vol.  II.) 

Volatile  oils  are  also  found  in  other  members  of  the  Rutaceae. 
The  garden  rue  (Ruta  graveolens),  the  leaves  of  which  are  used 
in  medicine,  contains  a  volatile  oil  consisting  of  several  ketones. 
It  also  contains  a  glucoside  known  as  rutin  which  resembles  the 
barosmin  of  buchu  ;  and  quercetin,  which  is  said  to  be  derived  from 
rutin.  The  Hop  tree  (Ptelea  trifoliata)  of  Eastern  North  Amer- 
ica contains  besides  a  volatile  oil,  a  resin  and  an  alkaloid.  The 
volatile  oil  of  pepper-moor  (Zanthoxylum  piperitum)  of  China 
and  Japan  is  known  as  Japanese  oil  of  pepper. 

ANGUSTURA  BARK  obtained  from  Cusparia  trifoliata  or  C. 
officinalis,  plants  growing  in  the  region  of  the  Orinoco  River,  con- 
tains a  volatile  oil,  resin,  a  bitter  principle  and  four  alkaloids. 
The  wood  of  Amyris  balsamifera  of  Guiana  and  Jamaica,  yields 
on  distillation  a  volatile  oil  resembling  Oleum  Rhodii. 

h.  SIMARUBACE;E  OR  AILANTHUS  FAMILY.— The 

plants  are  chiefly  shrubs  or  trees  with  alternate  and  pinnately- 
compound  leaves.  The  flowers  are  regular,  dioecious  or  polyg- 
amous and  in  axillary  racemes.  The  plants  are  natives  of  tropical 
countries  and  are  distinguished  from  the  Rutaceae,  which  they 
somewhat  resemble  by  the  absence  of  oil  secretory  cavities.  They 
are  widely  employed  particularly  in  the  tropics,  on  account  of  their 
bitter  principles,  and  are  considered  valuable  tonics,  febrifuges 
and  remedies  for  dysentery. 

Picrasma  excelsa  is  a  small  tree  with  9-  to  I7~foliate  leaves, 
the  leaflets  being  ovate  and  more  or  less  tomentose,  particularly 
in  the  bud ;  the  flowers  are  yellow,  polygamous  and  in  axillary 
panicles ;  the  fruit  is  a  large,  spherical  drupe.  The  wood  of  the 
plant  constitutes  Jamaica  quassia. 


586  A  TEXT-BOOK  OF  BOTANY. 

Quassia  amara  is  a  small  tree  or  shrub  with  4-  to  5-foliate 
leaves;  the  leaflets  are  narrow,  obovate  and  acuminate,  and  the 
rachis  and  petiole  or  stalk  are  winged ;  the  flowers  are  her- 
maphrodite, with  10  stamens,  bright  red  corolla,  and  in  terminal 
racemes;  the  fruit  is  a  5-valved  indehiscent  pod  or  nutlet.  The 
wood  constitutes  Surinam  quassia. 

A  red  coloring  principle  is  found  in  Samadera  indica  of  India, 
Ceylon  and  Java.  The  alkaloid  cedronin  is  found  in  the  seeds  of 
Simaba  Cedron  of  New  Granada,  the  seeds  being  used  as  an  anti- 
dote for  the  bites  of  poisonous  animals.  A  similar  principle  may 
exist  in  the  bark  of  Simaruba  versicolor  of  Brazil,  the  plant  being 
used  for  a  similar  purpose.  The  alkaloid  brucamarine  is  found 
in  the  fruit  of  Brucea  sumatrana.  A  tragacanth-like  gum  is 
obtained  from  Ailanthus  excelsa  of  India.  DIKA  or  GABUN  CHOC- 
OLATE is  obtained  from  the  seeds  of  Irvingla  gabonensis  of  trop- 
ical West  Africa.  Cay-Cay-Butter  is  obtained  from  the  seeds  of 
Irvingia  Oliveri  and  /.  malayana  of  Malacca  and  Cochin  China. 

A  gum  resembling  acacia  is  also  obtained  from  the  bark,  peti- 
oles and  seeds  of  the  species  of  Irvingia. 

i.  BURSERACE^:  OR  MYRRH  FAMILY.— The  plants  are 
shrubs  or  trees,  the  latter  being  sometimes  quite  large,  with 
resin-canals  in  the  bark,  and  alternate  compound  leaves ;  the 
flowers  are  small,  occurring  in  racemes.  The  members  of  this 
family  are  found  in  tropical  countries. 

Commiphora  abyssinica  is  a  shrub  10  M.  high,  the  branches 
being  modified  to  thorns ;  the  leaves  are  trifoliate,  the  leaflets  being 
oblong,  dentate,  sessile  and  the  terminal  one  much  larger  than 
the  other  two ;  the  flowers  are  dioecious,  and  the  fruit  is  a  drupe 
with  a  fleshy,  resinous  sarcocarp.  The  official  Myrrh  is  probably 
obtained  from  this  plant  as  well  as  other  species  of  Commiphora. 

A  number  of  other  resinous  products  are  yielded  by  plants  of 
this  family.  West  India  ELEMI  resin  or  Elemi  Occidentale 
(Anime)  is  obtained  from  the  stems  of  Protium  Icicariba  of 
Brazil.  The  resin  is  greenish-yellow,  soft,  with  a  bitter  taste  and 
dill-like  odor.  Manila  Elemi  is  a  soft,  granular,  lemon-yellow  or 
grayish-white  resin  derived  from  Canarium  commune  of  the 
Philippine  Islands.  Bengal  Elemi  is  derived  from  Commiphora 
Agallocha  of  the  East  Indies  and  Madagascar.  The  TACAMAHAC 


CLASSIFICATION  OF  ANGIOSPERMS.  587 

RESINS  are  balsamic  resins,  of  which  there  are  several  commercial 
varieties :  Mauritius  tacamahaca  is  obtained  from  Protium  hepta- 
phyllum  of  Columbia,  and  Mexican  or  West  Indian  tacamahaca 
from  Bursera  tomentosa  of  Mexico,  West  Indies,  and  South 
America.  INDIA  BDELLIUM  is  a  resin  obtained  from  the  bark  of 
Commiphora  Roxburghiana  of  Northwestern  India  and  Belu- 


•*  T  I  J 


FIG.  325.  Myrrh  plant  (Commiphora  abyssinica):  A,  young  branch  showing  tri- 
foliate leaves;  B,  flowering  and  fruiting  stem  with  thorn-like  branches;  C,  leaf  axis  in  which 
occur  a  fruit  and  staminate  and  pistillate  flowers;  D,  staminate  flower  in  longitudinal 
section;  E,  longitudinal  section  of  pistillate  flower;  F,  longitudinal  section  of  fruit  showing 
arillus-like  mesocarp  and  the  easily  dehiscent  endocarp.  —  After  Engler. 

chistan.  CopAL-like  resins  are  obtained  from  Canarium  ben- 
galense  (East  Indian  Copal)  and  possibly  several  species  of  Bur- 
sera.  BLACK  DAMMAR  resin  is  obtained  from  Canarium  ros- 
tratum  of  the  Molucca  Islands.  OLIBANUM  or  Frankincense  is  a 
gum-resin  obtained  from  several  species  of  Boswellia  of  Asia  and 
Somaliland.  AMERICAN  OLIBANUM  or  Soft  Resin  of  Cayenne 
exudes  spontaneously  from  the  stems  of  Protium  heptaphyllum 
and  P.  guianense.  GILEAD  BALSAM  is  obtained  from  Protium 


588  A  TEXT-BOOK  OF  BOTANY. 

altissimum  and  P.  Carana  of  Guiana  and  Brazil.  MEXICAN  LIN- 
ALCE  OIL  is  obtained  from  Bursera  graveolens,  and  several  species 
of  Bursera  of  Mexico  are  used  as  a  substitute  for  Aloe  wood. 

/.  MELIACE^E  OR  MAHOGANY  FAMILY.— This  is  a 
large  family  of  tropical  trees  and  shrubs  with  mostly  alternate, 
compound  and  exstipulate  leaves,  the  leaflets  being  entire,  with 
secretion  cells,  but  not  glandular-punctate  (Fig.  326).  The  flowers 


FIG.  326.     Pride  of  China  (Melia  Azedarach):  A,  flowering  branch;  B,  a  part 
of  the  inflorescence. — After  Harms. 

are  complete,  the  filaments  being  united  into  a  tube ;  and  they 
occur  in  axillary  clusters  or  racemes ;  the  fruit  is  a  capsule,  berry 
or  drupe ;  the  seeds  are  sometimes  winged  and  with  fleshy  or  leaf- 
like  cotyledons. 

The  bitter  principle  mangrovin  is  found  in  the  bark  of  the 
China  Tree  or  Pride  of  China  (Melia  Azedarach)  indigenous  to 
Asia,  and  extensively  cultivated  in  tropical  and  warm-temperate 
regions,  and  naturalized  in  the  southern  part  of  the  United  States 
(Fig.  326).  A  similar  principle  is  found  in  other  plants  of  this 
family. 


CLASSIFICATION  OF  ANGIOSPERMS.  589 

Carapa  Oil,  which  has  a  characteristic  odor  and  bitter  taste 
and  is  toxic  to  insects,  is  obtained  from  the  seeds  of  Carapa  pro- 
cera  and  C.  guianensis,  of  tropical  West  Africa  and  tropical 
America,  and  also  from  Swietenia  Mahagoni  (Mahogany  Tree). 
Cedar- wood  oil  ("Oleum  Cedreke  ")  is  obtained  from  several 
species  of  Cedrela  growing  in  tropical  America.  The  most  impor- 
tant constituent  of  the  oils  is  cadinine.  Oils  with  a  garlic-like 
odor  are  found  in  the  seeds  of  Melia  Azedarach,  the  bark  of 
Cedrela  australis  of  Australia  and  the  fruit  of  Dysoxylum  binec- 
tariferum  of  Java.  Besides  the  Mahogany  tree  there  are  other 
trees  of  this  family  which  yield  valuable  woods.  Cigar  boxes  and 
sugar  boxes  are  made  from  the  wood  of  Cedrela  odorata  of  the 
West  Indies  and  Guiana,  and  from  other  species  of  Cedrela. 

k.  MALPIGHIACE^E  is  a  rather  large  family  of  shrubs, 
small  trees,  or  lianes  with  anomalous  stem-structure,  •  found  in 
the  Tropics,  principally  in  South  America.  The  leaves  are  usually 
opposite,  the  sepals  are  glandular,  and  the  fruit  is  a  winged  samara 
somewhat  like  that  of  maple  (Acer). 

The  plants  contain  a  notable  amount  of  tannin  and  the  woods 
of  some  species  contain  a  red  coloring  principle. 

/.  POLYGALACE^:  OR  MILKWORT  FAMILY.— The 
members  of  this  family  are  herbs  or  shrubs,  occurring  in  all  parts 
of  the  world  except  in  the  Arctic  regions. 

Polygala  Senega  is  a  perennial  herb  about  ^3  M.  high.  It  has 
a  fleshy  root,  producing  at  the  crown  a  large  number  of  buds  and 
giving  rise  to  a  cluster  of  overground  stems  or  so-called  plants. 
The  leaves  are  alternate,  lanceolate  or  oblong-lanceolate  and  ses- 
sile ;  the  flowers  are  faintly  greenish- white  and  in  cylindrical 
spikes ;  the  capsule  is  loculicidally  dehiscent,  and  the  seed  is  hairy 
and  slightly  longer  than  the  lobes  of  the  caruncle.  The  root  is 
official. 

Polygala  alba  or  White  Milkwort  yields  the  White  or  Texas 
Senega.  The  stems  are  numerous  and  taller  than  those  of  P.  Sen- 
ega; the  leaves  are  narrow-lanceolate  or  linear  with  revolute  mar- 
gin ;  the  flowers  are  white  and  in  elongated  conic  spikes ;  the 
caruncle  lobes  are  about  half  as  long  as  the  seed.  The  plant  is 
found  west  of  the  Mississippi  River,  extending  as  far  south  as 
Texas  and  Mexico  and  west  as  far  as  Arizona  and  New  Mexico. 


590 


A  TEXT-BOOK  OF  BOTANY. 


m.  EUPHORBIACE^:  OR  SPURGE  FAMILY.— The 
plants  are  herbs,  shrubs  or  trees  with  acrid  and  often  milky 
latex.  The  fruit  is  mostly  a  trilocular,  dehiscent  capsule ;  the  seeds 
are  anatropous  and  have  an  oily  endosperm. 


FIG.  327.      Stillingia  sylvatica:  showing  the  more  or  less  closely  arranged  leaves 
and  the  terminal  spike  of  flowers. — After  Bentley  and  Trimen. 

Stillingia  sylvatica  or  Queen's-Root  yields  the  official  Stillingia 
(Fig.  327).  The  plant  is  a  perennial  herb  about  I  M.  high  and 
diffusely  branched.  The  leaves  are  obovate,  short-petiolate,  with 
glandular-serrate  margin ;  the  flowers  are  in  terminal  spikes,  light 
yellow,  monoecious,  the  staminate  being  above  and  the  pistillate 
below,  the  latter  solitary  in  the  axils  of  the  lower  bractlets. 


CLASSIFICATION  OF  ANGIOSPERMS.  591 

Ricinus  communis  or  Castor-Oil  Plant  is  an  annual  herb  in  the 
temperate  regions  but  is  shrub-like  and  perennial  in  tropical  and 
sub-tropical  countries.  In  temperate  regions  the  plant  is  from 
i  to  5  M.  high ;  the  leaves  are  peltate  and  6-  to  i  i-palmately-lobed ; 
the  flowers  are  greenish,  apetalous,  monoecious  and  in  racemes, 
the  pistillate  being  above  the  staminate  on  the  flower-axis;  the 
fruit  is  a  3-locular,  oval,  spinous  capsule,  which  dehisces  septi- 
cidally  (Fig.  237,  B).  The  seeds  are  anatropous,  somewhat  flat- 
tened-oblong ;  10  to  16  mm.  long  and  4  to  8  mm.  in  diameter; 
smooth,  mottled  grayish-brown  or  yellowish-red,  with  a  promi- 
nent caruncle ;  hard  but  brittle  testa,  thin  white  tegmen,  large  oily 
endosperm,  and  thin  foliaceous  cotyledons  at  the  center.  The 
seeds  contain  45  to  50  per  cent,  of  oil  which  constitutes  the  Castor 
Oil  of  medicine  and  a  large  amount  of  proteins  in  the  form  of 
aleurone  grains  (Fig.  250,  D).  The  cake  from  which  the  oil  is 
expressed  contains  a  poisonous  principle  known  as  ricin  which 
is  apparently  poisonous  to  cattle,  but  not  to  poultry. 

Croton  Tiglium  is  a  shrub  or  small  tree  indigenous  to  tropical 
Asia  and  extensively  cultivated  in  tropical  countries;  the  leaves 
are  alternate,  oblong-lanceolate  with  petioles  which  are  glandular 
at  the  base,  but  wanting  in  the  star-shaped  hairs  so  characteristic 
of  other  species  of  this  genus ;  the  flowers  are  small,  monoecious 
and  in  terminal  racemes,  the  pistillate  being  above  and  the  stam- 
inate below ;  the  fruit  is  a  3-locular,  septicidally  dehiscent  capsule. 
The  seeds  resemble  those  of  Ricinus  in  size  and  structure,  except 
that  they  are  less  smooth,  more  brownish  in  color  and  the  caruncle 
is  quite  small. 

They  contain  a  fixed  oil  which  is  obtained  by  expression  and 
which  is  poisonous  and  a  powerful  cathartic.  The  seeds  of  a 
number  of  the  other  members  of  the  Euphorbiaceae  contain  fixed 
oils  resembling  those  of  Croton  and  Ricinus,  as  CURCAS,  the  seeds 
of  Jatropha  Curcas  of  tropical  America.  MEXICAN  CROTON  OIL 
is  obtained  from  th«  seeds  of  Euphorbia  calyculata.  The  seeds  of 
the  Caper  Spurge  or  Wild  Caper  (Euphorbia  Lathyris),  nat- 
uralized in  the  United  States  from  Europe,  also  contain  a  fixed 
oil  resembling  that  of  Croton.  The  seeds  of  Joannesia  Princeps 
of  the  maritime  provinces  of  Brazil  are  also  powerful  purgatives. 

Mallotus  philippinensis  is  a  shrub  or  small  tree  found  in  trop- 


592  A  TEXT-BOOK  OF  BOTANY. 

ical  countries  of  the  Eastern  Hemisphere:  The  leaves  are  alter- 
nate, petiolate,  ovate,  acuminate,  coriaceous  and  evergreen;  the 
flowers  are  small,  dioecious,  and  in  racemes ;  the  fruit  is  a  3-locular, 
glandular-hairy  capsule.  The  hairs  of  the  capsule  are  official  in  a 
number  of  pharmacopoeias  under  the  name  of  KAMALA  and  occur 
as  a  reddish-brown,  granular  powder,  consisting  of  two  kinds  of 
hairs,  the  one  colorless  and  occurring  in  branching  clusters  (Fig. 
151)  and  the  other  with  yellowish-red,  multicellular,  glandular 
heads.  The  important  constituent  is  about  80  per  cent,  of  a  dark 
brownish-red  resin  composed  of  a  crystalline  principle  rottlerin, 
isorottlerin,  two  reddish-yellow  resins,  a  coloring  principle  and 
wax.  It  also  contains  a  trace  of  volatile  oil,  starch,  sugar,  tannin, 
oxalic  and  citric  acids. 

A  red  coloring  principle  is  found  in  the  bark  of  Aleurites 
triloba  of  the  Polynesian  Islands,  Euphorbia  parviflora  of  Ceylon, 
E.  pulcherrima  of  Mexico  and  Brazil  and  the  other  species  of 
Euphorbia. 

CASCARILLA  BARK  is  obtained  from  Croton  Eluteria  and  other 
species  of  Croton  growing  in  the  Bahama  Islands  and  other  parts 
of  the  West  Indies  and  Florida.  Cascarilla  bark  is  official  in  a 
number  of  pharmacopoeias.  It  occurs  in  small  curved  pieces  or 
quills,  i  to  3  mm.  thick,  externally  brownish-gray ;  inner  surface  is 
reddish-brown,  the  fracture  short,  resinous  ;  odor  aromatic  ;  partic- 
ularly on  burning;  taste  aromatic  and  bitter.  Cascarilla  contains 
I  to  1.5  per  cent,  of  a  volatile  oil,  containing  eugenol,  limonene,  an 
oxygenated  portion,  and  some  other  constituents;  15  per  cent,  of 
resin ;  a  bitter  principle,  cascarillin ;  tannin  and  vanillin. 

COPALCHI  BARK  or  Quina  blanca  which  is  derived  from  Croton 
niveus  of  Mexico  contains  a  bitter  principle,  copalchin,  which  is 
also  found  in  other  species  of  Croton.  Malambo  bark  is  derived 
from  Croton  Malambo  of  Venezuela,  the  latter  two  barks  being 
sometimes  substituted  for  Cascarilla  bark. 

ELASTICA  or  India  Rubber  (Caoutchouc)  is  the  prepared  milk- 
juice  obtained  from  one  or  more  species  of  the  following  genera : 
Hevea,  Mabea,  Euphorbia,  etc.  (see  pp.  238-241).  The  fresh 
latex  of  a  number  of  species  is  a  powerful  irritant,  as  that  of  the 
Sand-box  tree  (Hura  crepitans]  of  tropical  America,  which  con- 
tains a  highly  toxic  albuminoid;  the  Blinding-tree  (Excrecaria 


CLASSIFICATION  OF  ANGIOSPERMS.  593 

Agallocha)  of  Southern  Asia  and  Australia,  the  juice  of  which 
produces  blindness. 

The  gum-resin  EUPHORBIUM  is  obtained  from  Euphorbia  res- 
inifera,  a  cactus-like  plant  of  Morocco,  and  is  also  found  in  other 
species  of  Euphorbia.  It  contains,  among  other  constituents,  38 
per  cent,  of  an  acrid  resin,  and  22  per  cent,  of  a  crystalline  prin- 
ciple euphorbon. 

The  milk-juice  of  several  species  of  Euphorbia  is  used  in  the 
preparation  of  arrow  poisons  in  Brazil.  One  or  more  species  of 
the  following  genera  are  used  as  fish  poisons :  Flueggea,  Phyl- 
lanthus,  Bridelia,  Exccecaria  and  Euphorbia.  A  number  of  plants 
are  used  as  remedies  for  the  bites  of  serpents,  as  the  bark  of 
Phyllanthus  mollis  of  Java  and  Euphorbia  pilulifera  of  South 
America  and  India.  Euphorbia  pilulifera,  common  in  tropical 
countries,  contains  an  alkaloid,  a  wax-like  substance,  several 
resins  and  tannin.  (Ph.  Jour.,  29,  July  31,  1909,  p.  141.) 

A  camphor-containing  oil  is  found  in  the  bark  of  Pentalo- 
stigma  quadriloculare  of  Australia;  the  aromatic  wood  of  Col- 
liguaya  odorifera  of  Chile  is  used  as  a  substitute  for  santal  and 
on  burning  emits  a  rose-like  odor;  the  leaf  of  Croton  mentho- 
dorus  of  Peru  contains  an  oil  with  an  odor  of  mentha ;  a  balsam 
resembling  Copaiba  is  derived  from  the  bark  of  Croton  origani- 
folius  of  the  West  Indies ;  methylamine  is  found  in  Mercurialis 
annua  of  Europe  and  other  species  of  Mercurialis.  Tannin  is 
found  in  the  following  genera:  Macaranga,  Phyllanthus  and 
Bridelia;  Brazil  kino  is  obtained  from  a  species  of  Croton  (C. 
erythrceus?)  of  Brazil.  A  gum-lac  is  formed  on  the  stems  of 
Aleurites  laccifera  of  the  Antilles  and  Ceylon  as  a  result  of  the 
sting  of  an  insect,  and  contains  among  other  substances  a  large 
amount  of  methyl-  and  ceryl-alcohols,  and  a  substance  resembling 
abietic  acid.  The  sap  of  Euphorbia  Cyparissias  of  Europe  yields 
a  resin  which  is  sometimes  substituted  for  scammony. 

A  reddish  resinous  substance  resembling  dragon's  blood  is 
obtained  from  Croton  erythrema  of  Brazil;  a  yellow  coloring 
principle  is  found  in  the  seed  of  Croton  tinctorius  of  Mexico; 
poncetin,  a  violet  coloring  principle,  occurs  in  Euphorbia  hetero- 
phylla  of  Brazil;  a  blue  coloring  principle  is  found  in  Chrozo- 

phora  tinctoria  of  Southern  Europe  and  Africa  and  in  Argitham- 
38 


594  A  TEXT-BOOK  OF  BOTANY. 

nia  tricuspidata  lanceolata  of  Chile;  an  indigo-like  principle  is 
obtained  from  Mercurialis  perennis  of  Europe.  The  fresh  latex 
of  Euphorbia  phosphorea  of  Brazil  is  phosphorescent. 

Quite  a  number  of  the  seeds  of  this  family  contain  fatty  oils. 
The  Chinese  Tallow  tree  (Sapium  sebiferum)  yields  a  fat  which 
is  used  for  burning  and  for  technical  purposes ;  a  similar  fat  is 
obtained  from  the  seeds  of  several  species  of  Aleurites  and 
Euphorbia. 

TAPIOCA  starch  is  derived  from  the  tuberous  roots  of  Manihot 
utilissima,  extensively  cultivated  in  tropical  countries;  other  spe- 
cies of  Manihot  also  yield  starchy  food  products. 

Edible  fruits  are  obtained  from  the  following  genera :  Phyl- 
lanthus,  Baccaurea  and  Antidesma ;  the  seeds  of  Hevea  brasiliensis 
are  edible ;  a  sweet  sap  is  found  in  Baccaurea  ramiftora  of  Cochin 
China  and  Brazil ;  a  peptone-like  ferment  is  found  in  Euphorbia 
heterodoxa  of  South  America  and  other  species  of  Euphorbia. 

XVII.    ORDER   SAPINDALES. 

The  plants  of  this  order  are  chiefly  trees  and  shrubs.  The 
flowers  are  mostly  regular  and  the  seeds  usually  without  endo- 
sperm. The  order  has  a  number  of  representatives  in  both  tropical 
and  temperate  regions. 

a.  BUXACE^  OR  BOX  TREE  FAMILY.— The  plants  are 
shrubs  with  alternate  or  opposite,  evergreen  leaves,  and  usually 
axillary  monoecious  or  dicecious  flowers.     The  most   important 
plant  of  this  family  is  the  Box  tree  (Buxus  sempervirens) ,  which 
is  extensively  cultivated.     The  wood  is  used  for  making  musical 
instruments  and  for  other  purposes,  and  the  twigs  have  been  used 
in  medicine.    The  latter  contain  several  alkaloids,  the  most  impor- 
tant being  buxine,  which  resembles  beberine ;  a  volatile  oil  con- 
taining butyric  acid  and  a  wax  containing  myricyl  alcohol  and 
myricin. 

b.  FAMILY  CORIARACE^E.— This   family  is  represented 
by  but  a  single  genus,  Coriaria.     The  plants  are  shrubs  found 
in  Europe,  Asia  and  South  America,  and  yield  several  important 
economic  products.     The  leaves  and  bark  of  C.  myrtifolia  of 
Southern  Europe  and  Northern  Africa  are  rich  in  tannin  and  used 
in  dyeing.     This  plant  also  contains  a  narcotic  principle,  resem- 


CLASSIFICATION  OF  ANGIOSPERMS.  595 

blmg  picrotoxin,  known  as  coriamyrtin,  which  is  also  found  prob- 
ably in  C.  atropurpurea  of  Mexico.  The  leaves  of  Coriaria  myrti- 
folia  or  TANNER'S  SUMAC  are  coriaceous,  distinctly  3-nerved, 
astringent  and  bitter  and  were  at  one  time  substituted  for  senna 
leaves.  A  black  dye  is  obtained  from  C.  ruscifolia  of  New  Zealand 
and  Chile.  While  the  fruits  of  some  species  are  quite  poisonous, 
the  sap  of  the  fleshy  leaves  is  used  in  New  Zealand  in  making 
an  intoxicating  drink. 

c.  ANACARDIACE^E  OR  SUMAC  FAMILY.— The  plants 
are  trees  or  shrubs  with  an  acrid,  resinous  or  milky  latex,  and 
alternate  leaves. 

Rhus  Toxicodendron,  POISON  IVY  or  Poison  Oak,  is  a  woody 
vine,  climbing  by  means  of  aerial  roots  and  sometimes  becoming 
quite  shrub-like,  which  is  common  along  roadsides  in  the  United 
States.  The  leaves  are  3-foliate,  the  leaflets  being  ovate,  acumi- 
nate, nearly  entire,  inequilateral  and  with  short  stalks ;  the  flowers 
are  green  and  in  loose  axillary  panicles ;  the  fruit  is  a  globular, 
glabrous,  grayish  drupe  (Fig.  328).  The  nature  of  the  poisonous 
constituents  of  Poison  Ivy  is  not  definitely  known.  It  was  orig- 
inally considered  to  be  in  the  nature  of  a  volatile  principle.  Pfaff 
and  his  pupils  seemed  to  show  that  the  poisonous  principle  was  a 
non-volatile  brownish-red  resin  which  is  soluble  in  alcohol  and 
called  toxicodendrol.  Schwalbe,  on  the  other  hand,  states  that 
the  poisonous  substance  is  of  a  volatile  nature,  being  formed  in  the 
laticiferous  vessels  and  by  osmosis  is  transferred  to  the  hairs. 
The  poison  may  be  transmitted  either  by  direct  contact  with  the 
hairs,  much  as  in  the  same  manner  with  the  nettles,  or  by  volatiliza- 
tion of  the  oil  when  the  hairs  are  broken.  The  experience  of  most 
plant  collectors  would  seem  to  indicate  that  in  Poison  Ivy  there 
is  a  volatile  toxic  constituent  (Amer.  Jour.  Pharm.,  March,  1914). 
On  the  other  hand,  Rost  and  Gilg  were  unable  to  find  a  volatile 
poison  in  either  the  hairs  or  pollen  of  Poison  Ivy.  In  some  ex- 
periments conducted  by  Warren  on  pollen  grains,  similar  negative 
results  were  obtained  {Amer.  Jour.  Pharm.,  Dec.,  1913).  The 
poisonous  principle  occurring  in  several  species  of  Rhus  is  an 
amber-red,  non-volatile  liquid.  It  is  of  a  resinous  nature,  com- 
bining with  the  alkali  hydroxides  to  form  nigrescent  compounds, 
and  otherwise  behaves  like  certain  phenolic  compounds.  The  toxic 


59^ 


A  TEXT-BOOK  OF  BOTANY. 


resin  exists  in  the  plant  in  the  form  of  an  emulsion  which  readily 
blackens  with  the  alkali  hydroxides.  So  delicate  is  this  reaction 
that  minute  amounts  of  the  substance  may  be  detected  by  means 


FIG.  328.    Leaves  and  fruit  of  the  poison  ivy  (Rhus  radicans).    This  is  a  3-foliate  com- 
pound  leaf,  the  leaflets  being  ovate  and  having  veins  which  bifurcate  and  end  free. 

of  the  microscope  if  the  plant  tissues  are  mounted  in  an  alcoholic 
solution  of  potassium  hydroxide.  A  vesicating  principle  CARDOL 
is  found  in  the  CASHEW  NUT.  The  latter  is  the  fruit  of  Anacardium 


CLASSIFICATION  OF  ANGIOSPERMS.  597 

occidentale,  a  shrub  growing  in  tropical  America.  A  principle 
resembling  cardol  is  found  in  the  East  India  Marking  tree  or  Ink 
tree (Seniecar pus  Anacardium)a.nd  Holigarna  ferruginea  of  India. 

The  POISON  SUMAC  or  Poison  Elder  (Rhus  Vernix)  is  a  shrub 
or  small  tree  found  in  swamps  in  the  United  States  and  Canada. 
The  leaves  are  7-  to  13-foliate,  with  obovate  or  oval,  acuminate, 
entire  leaflets ;  the  flowers  are  small,  green,  and  in  axillary  pani- 
cles;  the  fruit  resembles  that  of  R.  radicans  (Fig.  328).  The 
plant  is  poisonous  like  R.  Toxicodendron  and  probably  contains  the 
same  principle.  Other  species  of  Rhus  are  also  poisonous,  as  the 
western  Poison  Oak  (R.  diversiloba)  of  the  Pacific  Coast,  and 
the  Japanese  Lacquer  or  Varnish  tree  (R.  vernicifera  and  R. 
succedanea).  The  lacquer  trees  grow  wild  in  both  China  and 
Japan,  where  they  are  also  cultivated.  The  lac  is  obtained  by 
incising  the  bark  and  removing  it  with  a  pointed  spatula.  The 
grayish-white  emulsion  is  strained  and  on  exposure  to  air  it 
changes  to  brown,  becoming  finally  black.  This  change  is  due  to 
the  oxidizing  enzyme  laccase.  The  natural  lac  (Kiurushi)  contains 
a  non-volatile  poisonous  resin-like  principle  and  is  closely  associ- 
ated with  other  resinous  substances.  Japanese  lac  is  thinned  with 
camphor,  or  mixed  with  linseed  oil,  and  on  drying  in  a  moist  atmos- 
phere forms  the  most  indestructible  varnish  known.  Various  pig- 
ments are  used,  as  vermilion,  gamboge,  acetate  of  iron  and  other 
substances.  The  best  glossy  black  colors  are  obtained  by  the 
addition  of  iron. 

Rhus  glabra  or  the  Scarlet  Sumac  is  a  smooth  shrub.  The  leaves 
are  n-  to  31 -foliate,  the  leaflets  being  lanceolate,  acuminate,  sharply 
serrate,  dark  green  above  and  lower  face  glaucous ;  the  flowers  are 
greenish,  polygamous  and  in  terminal  panicles ;  the  fruits  of  this 
plant  and  of  R.  typhina  (Fig.  329)  are  used  in  medicine. 

CHINESE  GALLS  are  excrescences  produced  on  Rhus  semialata 
as  a  result  of  the  stings  of  an  Aphis.  JAPANESE  GALLS  are  similar 
formations  occurring  on  Rhus  japonica.  (See  pp.  206,  334.) 

Pistacia  Lentiscus  is  a  shrub  or  tree,  which  is  found  growing 
in  the  Grecian  Archipelago.  The  leaves  are  pinnately  compound 
and  with  winged  axis,  the  leaflets  being  alternate,  oblong,  entire, 
sessile;  the  flowers  are  small,  dioecious,  and  in  axillary  clusters. 
In  the  bark  of  this  plant  there  are  large  cavities  which  contain 


598 


A  TEXT-BOOK  OF  BOTANY. 


\ 


FIG.  329.  Fruiting  branch  with  leaves  of  Rhus  typhina.  Reproduced  from  Sargent's 
"Silva  of  North  America." 

Rhus  typhina  is  commonly  known  as  the  "  staghorn  sumac"  in  allusion  to  the  soft 
brown  pubescence  covering  the  twigs  and  branches.  It  is  also  known  as  the  "  vinegar  tree  " 
and  "  Virginia  sumac."  It  may  attain  the  height  of  a  tree,  and  is  usually  found  growing  in 
uplands  in  good  soil,  ocasionally  being  found  like  Rhus  glabra  on  barren  gravelly  banks.  It 
is  very  abundant  in  the  eastern  United  States  and  apparently  sparingly  distributed  west  of 
the  Appalachian  Mountains. 


CLASSIFICATION  OF  ANGIOSPERMS.  599 

an  oleo-resin  that  is  official  as  Mastic  in  a  number  of  pharmaco- 
poeias (see  Vol.  II).  The  wood  of  Schinopsis  Lorentzii  and  S. 
Balansa,  growing  in  Argentine  and  Paraguay,  is  known  in  com- 
merce as  QUEBRACHO  COLORADO.  It  is  red,  very  hard  and  contains 
tannin,  gallic  and  ellagic  acids. 

The  PISTACIO  nuts  or  Pistacia  almonds  are  obtained  from 
Pistacia  vera  indigenous  to  Syria  and  Mesopotamia  and  exten- 
sively cultivated  in  the  countries  bordering  the  Mediterranean. 
The  kernels  are  used  extensively  in  confectionery.  The  nuts  are 


FIG.  330.     Gallic  acid:  long  orthorhombic  crystals  obtained  from  an  aqueous  solution. 

about  20  mm.  long,  somewhat  quadrangular  in  cross  section,  and 
the  seed  consists  of  two  fleshy,  green  cotyledons.  The  seeds  of 
Buchanania  latifolia  and  other  species  of  Buchanania  are  used  in 
India  much  like  almonds. 

Gums  are  found  in  several  species  of  Anacardium  and  Sclero- 
carya.  ACAJOU  GUM  is  obtained  from  Anacardium  occidentale. 
Considerable  sugar  and  citric  acid  are  found  in  MANGOS,  the 
fruit  of  Mangifera  indica  native  of  Farther  India  and  Ceylon  and 
cultivated  in  the  Tropics.  A  fruit  used  like  lemons  is  obtained 
from  Dracontomelon  mangiferum  of  Malacca  and  the  Sunda 
Islands. 


6oo  A  TEXT-BOOK  OF  BOTANY. 

d.  AQUIFOLIACE^:   (ILICACE^E)   OR  HOLLY  FAM- 
ILY.— The  plants  are  mostly  shrubs  or  trees  with  alternate,  petio- 
late,  simple  leaves  and  small,  white,  regular  flowers.     The  fruit 
is  a  berry-like  drupe  containing  several  nutlets.     The  most  im- 
portant genus  of  this  family  is  Ilex,  a  number  of  species  of  which 
are  found  in  the  United  States. 

The  European  holly  (Ilex  Aquifolium)  contains  a  bitter  gluco- 
sidal  principle,  ilicin,  which  is  found  in  the  bark  as  well  as  the 
drupes.  The  drupes  contain  a  principle  which  is  a  homologue 
of  benzyl  alcohol,  and  a  glutinous  substance  which  renders  them 
useful  in  the  manufacture  of  bird  lime.  The  American  holly  (/. 
opaca)  growing  in  the  Eastern  United  States  probably  contains 
similar  constituents  to  the  European  holly.  This  is  the  plant 
which  furnishes  the  CHRISTMAS  HOLLY. 

MATE,  Paraguay  or  Brazilian  tea,  consists  of  the  leaves  of 
Ilex  paraguariensis  (Fig.  331)  found  in  Brazil,  Argentine  and 
Paraguay.  They  contain  about  2  per  cent,  of  caffeine,  1 1  per 
cent,  of  tannin  and  some  volatile  oil,  and  are  used  like  tea  in  the 
making  of  a  beverage.  Cassine  or  Appalachian  tea  consists  of 
the  leaves  of  the  Dahoon  holly  (Ilex  Cassine)  growing  in  the 
Southern  United  States.  These  leaves  contain  about  half  as  much 
caffeine  and  tannin  as  Mate. 

e.  CELASTRACE^:  OR  STAFF-TREE  FAMILY.— These 
are  shrubs,  as  Euonynms,  or  woody  climbers,  as  the  climbing  bit- 
tersweet (Celastrus  scandens).    The  plants  are  especially  charac- 
terized by  their  dehiscent  fruits  and  scarlet  or  reddish  arilled  seeds. 

Euonymus  atropurpureus  (Wahoo  or  Burning  Bush)  is  a 
shrub  or  small  tree.  The  twigs  have  four  distinct  cork-wings, 
making  them  somewhat  4-angled.  The  leaves  are  opposite,  petio- 
late,  ovate-oblong,  acuminate,  crenulate-serrulate  and  hairy  be- 
neath. The  flowers  are  purplish  and  in  axillary  cymes.  The  f  ruitJ 
is  a  3-  to  4-lobed,  persistent,  loculicidally  dehiscent  capsule  with 
6  to  8  scarlet  seeds.  The  bark  of  the  root  is  official. 

The  leaves  of  Catha  edulis  growing  in  Arabia  and  Abyssinia 
are  chewed  and  also  used  like  tea.  They  contain  the  alkaloids 
cathine  and  celastrine  which  are  supposed  to  have  similar  proper- 
ties to  cocaine,  as  well  as  tannin  and  an  ethereal  oil.  A  yellow 
coloring  principle  is  found  in  the  bark  of  Euonymus  tingens  of 


CLASSIFICATION  OF  ANGIOSPERMS. 


60 1 


>       6   I*   •  ' 

mm 


FIG.  331.  Yerba  Mate  trees  (Ilex  paraguariensis)  growing  in  Pereira  Continhoand 
Almeido,  Santos,  Brazil.  The  plants  are  shrubs  or  small  trees,  with  ovate  or  nearly  spatu- 
late,  dentate  and  slightly  coriaceous  leaves.  The  latter  are  used,  under  the  name  of  Para- 
guay tea,  in  the  preparation  of  a  tea-like  beverage.  The  trees  are  extensively  cultivated 
in  South  America,  and  large  quantities  of  Mate"  are  consumed  annually.  The  young  branches 
are  gathered  between  December  and  August,  dried  over  a  fire,  the  leaves  being  separated, 
and  are  then  ready  for  market. — Reproduced  by  permission  of  The  Philadelphia  Com- 
, mercial  Museum. 


602  A  TEXT-BOOK  OF  BOTANY. 

the  East  Indies.  The  yellow  coloring  principle  in  the  arils  of  the 
seeds  of  Celastrus  and  Euonymus  appears  to  closely  resemble 
carotin.  The  seeds  of  a  number  of  plants  of  this  family  contain 
a  considerable  quantity  of  fixed  oil,  as  Celastrus  macro  car  pus  of 
Peru,  and  Maytenus  Boaria  of  Chile. 

/.  ACERACE^:  OR  MAPLE  FAMILY.— The  plants  of  this 
family  are  trees  or  shrubs,  the  most  widely  distributed  repre- 
sentative of  which  is  the  maple  (Acer).  The  most  distinguishing 
character  of  this  family  is  the  fruit,  which  is  a  double  samara. 
The  sap  of  a  number  of  species  of  Acer  contains  cane  sugar  or 
sucrose,  and  the  sap  of  the  sugar  maple  (Acer  saccharinum)  which 
grows  in  the  United  States  and  Canada  contains  from  3  to  4  per 
cent.  The  making  of  maple  syrup  and  maple  sugar  is  quite  an 
industry  in  some  localities.  Maple  sugar  is  also  obtained  from 
the  black  sugar  maple  (Acer  nigrum)  and  the  ash-leaved  maple 
(A.  Negundo).  The  bark  of  the  latter  species  is  used  to  some 
extent  in  medicine.  Valuable  timber  is  yielded  by  the  maple  trees. 

g.  HIPPOCASTANACEyE  OR  BUCKEYE  FAMILY.— 
The  plants  are  shrubs  or  trees  with  opposite,  petiolate,  and  3-  to 
9-digitately-foliate  leaves.  The  flowers  are  in  terminal  panicles 
and  the  fruit  is  a  3-lobed  capsule,  which  usually  contains  one 
large,  shiny  seed. 

The  horse-chestnut  (sEsculus  Hippocastanum)  contains  in  the 
bark  two  fluorescent  bitter  principles,  sesculin  and  paviin,  the 
former  of  which  is  in  the  nature  of  a  glucoside ;  and  in  the  bark, 
leaves  and  flowers  the  coloring  principle,  quercitrin  is  present; 
in  the  seed-coat  saponin  is  supposed  to  occur,  and  the  glucoside 
sesculin  as  well.  The  cotyledons  contain  considerable  starch,  some 
proteins  and  sugar,  a  small  quantity  of  a  fixed  oil,  and  argyresin, 
to  which  the  antihemorrhoidal  action  appears  to  be  due.  A 
narcotic  principle  is  present  in  the  bark,  twigs  and  leaves  of  the 
red  buckeye  (JEsculus  Pavia)  of  the  Southern  United  States. 

h.  SAPINDACE^  OR  SOAPBERRY  FAMILY.— The 
plants  are  mostly  trees  or  shrubs  indigenous  to  the  Tropics.  In 
some  genera  they  are  herbaceous  or  woody  vines  (lianes).  The 
plants  of  this  family  usually  have  either  a  milky  sap  or  contain 
saponin,  and  it  seems  strange  that  a  plant  yielding  caffeine,  namely, 


CLASSIFICATION  OF  ANGIOSPERMS.  603 

Paullinia  Cupana,  which  furnishes  the  official  Guarana,  should 
belong  to  this  group. 

The  fruit  shells  of  Nephelium  lappaceum  contain  a  toxic  sapo- 
nin  (Ph.  Weekblad.,  45,  i,  156,  1908).     Four  or  five  per  cent. 


FIG.  332.    Flowering  and  fruiting  branch  of  Brazilian  cocoa  (Paullinia  Cupana)  yielding 
the  Guarana  used  in  medicine. — After  Radlkofer. 

of  SAPONIN  is  found  in  the  fruit  of  Sapindus  trifoliatus  of  India. 
A  principle  related  to  saponin  is  found  in  Sapindus  Saponaria  of 
tropical  America.  Saponin  is  also  found  in  the  fruits  of  other 
species  of  Sapindus,  the  bark  of  Pometia  pinnata  of  the  Sunda 


604  A  TEXT-BOOK  OF  BOTANY. 

and  South  Sea  Islands,  and  the  kernels  of  the  seeds  of  the  two 
species  of  Magonia  indigenous  to  Brazil.  The  latter  plants  also 
yield  a  poisonous  nectar  and  the  root-bark  is  used  in  the  poison- 
ing of  fish.  A  shellac  is  obtained  from  Schleichera  trijuga  of 
India  and  the  seeds  of  this  plant  yield  "  marcassa  oil." 

Paullinia  Cupana  is  a  woody  climber  indigenous  to  and  culti- 
vated in  Northern  and  Western  Brazil.  The  leaves  are  alternate 
and  5~foliate,  the  leaflets  being  oblong,  acuminate,  coarsely,  irreg- 
ularly dentate,  and  with  short  stalks ;  the  flowers  are  yellow  and 
in  axillary  panicles ;  the  fruit  is  a  3-locular,  3-seeded  sub-drupose 
capsule  (Fig.  332). 

i.  BALSAMINACE^E  OR  JEWEL-WEED  FAMILY.— 
The  plants  are  succulent  herbs  with  alternate,  petiolate  leaves  and 
conspicuous  axillary  flowers ;  the  fruit  is  a  capsule  which  at 
maturity  breaks  into  five  valves,  discharging  the  seeds  with  con- 
siderable force. 

The  balsam  of  the  gardens  (Impatiens  Balsamina),  which 
flowers  all  summer,  belongs  to  this  family.  Other  species  of 
Impatiens  are  also  cultivated. 

The  stem  sap  as  well  as  that  of  the  flowers  of  a  number  of 
species  of  Impatiens  is  used  on  account  of  its  red  and  yellow 
coloring  matters,  to  color  the  skin  of  the  hands  and  feet  as  also,  the 
nails  by  the  people  of  India,  Tartary  and  Japan.  The  seeds  of 
some  species  of  Impatiens  yield  an  oil  which  is  used  for  burning. 

XVIII.    ORDER  RHAMNALES. 

This  order  includes  two  large  families  which  are  characterized 
by  having  4  or  5  stamens  which  are  either  alternate  with  the  sepals 
or  opposite  the  petals  when  the  latter  are  present.  The  ovules 
are  atropous. 

a.  RHAMNACE^E  OR  BUCKTHORN  FAMILY.— The 
plants  are  woody  climbers,  shrubs  or  small  trees. 

Rhamnus  Purshianus  is  a  large  shrub  or  small  tree.  The  leaves 
are  petiolate,  oblong,  elliptical,  acuminate,  finely  serrate  and  pubes- 
cent beneath ;  the  flowers  are  small  and  in  axillary  umbellate 
cymes,  and  the  fruit  is  3-lobed,  black,  ovoid,  and  drupaceous. 
The  bark  constitutes  the  official  Cascara  sagrada  (Fig.  333). 

Rhamnus  Frangula  or  Alder  Buckthorn  is  a  shrub  the  botan- 


CLASSIFICATION  OF  ANGIOSPERMS.  605 

ical  characters  of  which  closely  resemble  those  of  R.  Purshianus. 
The  bark  of  this  plant  is  also  official. 


FIG.  333.     A   Cascara  tree  on   University   of   Washington   campus. — After  Johnson  and 
Hindman,  Amer.  Jour.  Pharm.,  1914,  p.  389. 

The  leaves  of  the  shrub  known  as  New  Jersey  Tea  (Ceanothus 
americamts)  are  said  to  have  been  used  as  a  substitute  for  tea 
during  the  Revolutionary  times.  This  plant  is  found  in  the  East- 


606  A  TEXT-BOOK  OF  BOTANY. 

ern  United  States  and  Canada  and  the  root,  which  contains  con- 
siderable tannin  and  possibly  an  alkaloid,  has  been  used  in  medi- 
cine. The  leaves  of  Sageretia  theezans  of  Asia  have  also  been 
used  as  a  substitute  for  tea.  A  number  of  plants  of  this  family 
have  been  SUBSTITUTED  FOR  HOPS  in  the  fermentation  industry,  as 
Ceanothus  reclinatus  of  the  West  Indies ;  Colubrina  fermenta  of 
Guiana,  and  Gouania  doming  ensis  of  Martinique  and  Hayti. 
Saponin  is  found  in  the  bark  of  Gouania  tomentosa  of  Mexico. 
A  crystalline  bitter  principle,  colletin,  occurs  in  the  wood  of  Col- 
letia  spinosa  of  South  America.  The  bark  of  Discaria  febrifuga 
of  Brazil  has  been  used  as  a  substitute  for  cinchona.  A  number 
of  genera  furnish  fish  poisons,  as  Zizyphus,  Tapura,  and  Gouania. 
Gum-lac  is  formed  on  the  twigs  of  Zizyphus  Jujuba  of  Asia  as 
the  result  of  the  sting  of  an  insect  (Coccus  lacca). 

The  fruits  of  several  species  of  Zizyphus,  thorny  shrubs  found 
growing  in  South  America,  are  edible  and  enter  into  the  French 
or  Spanish  confection  known  as  JUJUBE-PASTE. 

b.  VITACE^:  OR  GRAPE  FAMILY.— The  plants  of  this 
family  are  woody  climbers  or  erect  shrubs  with  alternate,  petiolate 
leaves,  and  small,  greenish,  regular  flowers,  the  fruit  being  a 
berry. 

The  most  important  genus,  economically,  is  Vitis,  to  which 
belong  the  cultivated  grapes,  the  fruits  of  which  furnish  raisins, 
wine  and  brandy.  The  GRAPE-VINE  indigenous  to  Europe  (Vitis 
vinifera)  is  cultivated  in  all  temperate  and  sub-tropical  countries, 
and  the  variety  silvestris  which  is  found  distributed  in  the  Medi- 
terranean countries  as  far  east  as  the  Caucasus  Mountains  is  sup- 
posed to  have  furnished  the  cultivated  wine  grape.  The  CONCORD 
and  CATAWBA  GRAPES  are  cultivated  varieties  of  the  northern  Fox- 
or  Plum-grape  (Vitis  Labrusca)  indigenous  to  the  Northern 
United  States  east  of  Minnesota.  The  DELAWARE  GRAPES  are  cul- 
tivated varieties  of  the  frost-grape  (V.  cordifolia)  and  the  sweet- 
scented  grape  (V.  vulpina)  of  the  Eastern  United  States.  The 
pulpy  part  of  the  grape  contains  from  9  to  18  per  cent,  of  grape- 
sugar  and  0.5  to  1.36  per  cent,  of  tartaric  acid.  In  unfavorable 
seasons  the  tartaric  acid  is  replaced  in  part  by  malic  acid.  The 
soil  has  a  marked  influence  on  the  quality  of  grapes,  a  sandy  soil 


CLASSIFICATION  OF  ANGIOSPERMS.  607 

producing  a  light  colored  wine,  a  soil  rich  in  calcium  a  sweet 
wine,  and  a  clay  soil  a  fine  bouquet,  etc. 

WINES  are  made  by  fermenting  the  grape  juice,  and  contain 
from  5  to  20  per  cent,  of  alcohol,  from  i  or  2  to  12  per  cent,  of 
sugar,  about  0.5  per  cent,  of  tartaric,  acetic  and  other  fruit-acids, 
tannin  and  coloring  matter  from  a  trace  to  0.3  per  cent.,  and 
various  compound  ethers,  giving  them  their  characteristic  flavors 
or  bouquets.  WHITE  WINES  are  made  from  the  juice  of  the  pulp 
of  the  white  or  colored  grapes  after  separation  from  the  epicarp 
and  seeds.  In  the  manufacture  of  RED  WINE  no  care  is  taken  to 
separate  the  seeds  and  skins  of  colored  grapes  or  even  the  stems 
on  which  the  fruits  are  borne.  PORT  WINE  is  made  from  a  grape 
grown  in  Portugal,  the  wine  being  chiefly  exported  from  Oporto. 
The  term  CLARET  is  applied  to  a  red  wine  containing  a  small 
amount  of  alcohol.  BRANDY  is  obtained  by  the  distillation  of  the 
fermented  juice  of  the  grape.  CHAMPAGNE  is  a  product  obtained 
by  fermenting  grape  juice  to  which  other  substances  have  been 
added,  and  contains  about  10  per  cent,  of  alcohol  and  67  per  cent, 
of  carbon  dioxide.  RAISINS  are  obtained  from  a  variety  of  Vitis 
vinifera  containing  a  high  percentage  of  sugar.  In  the  prepara- 
tion of  raisins  the  ripe  grapes  are  dried  either  by  exposure  to  the 
sun  or  artificial  heat.  In  grape  preserves  in  addition  to  the  indis- 
tinguishable cells  of  sarcocarp,  raphides  of  calcium  oxalate  occur. 

A  principle  resembling  toxicodendrol  is  found  in  Vitis  incon- 
stans  of  Japan.  A  greenish-blue  coloring  principle  occurs  in  Vitis 
sicyoides  of  South  America.  The  leaves  and  twigs  of  VIRGINIA 
CREEPER  or  American  ivy  (Psedera  quinquefolia)  contain  tartaric 
acid,  glycollic  acid,  catechin  and  inosit. 

XIX.   ORDER   MALVALES. 

This  order  includes  several  families  having  rather  diversified 
characters.  The  stamens  are  numerous,  the  sepals  are  valvate 
and  the  placentas  are  axillary. 

a.  FAMILY  EL^OCARPACE^.— The  members  of  this 
family  are  shrubs  or  trees  mostly  indigenous  -to  the  Tropics. 
They  are  distinguished  from  the  plants  of  the  other  families  of 
this  order  in  not  containing  lysigenous  mucilage  canals.  A  prin- 
ciple yielding  hydrocyanic  acid  is  found  in  Echinocarpus  Sigun 


6o8 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  334.  American  Linden,  Basswood  or  Lime  tree  (Tilia  americana}.  A,  flowering 
branch  showing  the  obliquely  heart-shaped,  serrate  leaves  with  conspicuous  midrib  and 
primary  veins,  and  cymose  clusters  of  yellowish-white  fragrant  flowers,  which  are  at- 
tached to  the  midvein  of  an  oblong,  leaf-like  bract.  B,  several  of  the  ovoid  or  spherical, 
nut-like  fruits  about  the  size  of  peas. — From  Bulletin  26,  U.  S.  Department  of  Agriculture. 

of  Java.  A  yellow  coloring  principle  is  found  in  the  leaves  of 
Vallea  cordifolia  of  Peru.  A  fatty  oil  is  found  in  the  seeds  of 
several  species  of  Elceocarpus.  A  number  of  fruits  of  this  family 


CLASSIFICATION  OF  ANGIOSPERMS.  609 

are  edible.  Maqui  Fruit  is  obtained  from  Aristotelia  Maqui  of 
Chile  and  is  used  to  color  wine.  The  seeds  of  Sloanea  dentata  are 
eaten  like  chestnuts  in  Guiana. 

b.  TILIACE^E  OR  LINDEN   FAMILY.— The  plants  are 
shrubs   or  trees  with   alternate,   simple  leaves,   and   with   white 
flowers  in  cymes  or  panicles.    In  the  Linden  or  Basswood  ( Tilia) 
the  peduncles  are  partly  adnate  with  the  long,  leaf-like  bracts. 
The  fruits  are  dry  drupes  (Fig.  334). 

The  flowers  of  the  European  Linden  (Tilia  europcca)  contain 
a  fragrant  volatile  oil  and  are  used  in  medicine.  The  flowers  of 
other  species  of  Tilia  also  contain  volatile  oils,  and  the  flowers  of 
Tilia  toment-osa  of  Southern  Europe  are  used  to  flavor  champagne. 
The  leaves  of  Tilia  europcea  contain  the  glucoside  tiliacin.  Sev- 
eral species  of  Grewia  are  used  as  fish  poisons.  A  purgative 
principle  is  found  in  the  seeds  of  Cor  chorus  olitorius  of  Southern 
Asia,  Africa  and  South  America.  A  bitter  principle  occurs  in 
the  seeds  of  Cor  chorus  tridens  of  Arabia,  India  and  Egypt.  A 
reddish-colored,  fatty  oil  known  as  APEIBA  OIL  is  obtained  from 
the  seeds  of  Apeiba  Tibourbon  of  Guiana.  The  root  of  Grewia 
scabrophylla  is  used  as  a  substitute  for  Althaea  in  India.  Mucilage 
is  found  in  the  flowers  and  fruits  of  a  number  of  genera.  The 
leaves  of  Corchorus  siliquosus  are  used  in  Panama  as  a  substitute 
for  tea.  A  number  of  the  fruits  of  this  family  are  edible,  as  of 
Muntingia  and  Apeiba.  The  bast  fibers  of  several  species  of  Cor- 
chorus, particularly  C.  capsularls  of  China  and  India,  constitute 
jute,  which  is  used  in  the  making  of  cordage.  The  fiber  is  sep- 
arated by  cold  retting  in  stagnant  water. 

c.  MALVACE^  OR  MALLOW  FAMILY.— The  plants  are 
mostly  herbs  or  shrubs  with  alternate,  simple  leaves,  and  regular, 
perfect,  large  flowers,  with  the  stamens  united  into  a  column  which 
encloses  the  styles  (Fig.  222,  E),  and  a  capsular  fruit.    The  culti- 
vated ornamental  Hollyhock  and  Althaea  belong  to  this  family. 

Althcea  officinalis  or  marshmallow  is  a  perennial  herb  about 
I  M.  high  with  broadly  ovate,  petiolate,  acute,  dentate  and  lobed, 
pubescent  leaves ;  the  flowers  are  2  to  4  in  number  in  the  axils  of 
the  leaves  and  have  rose-colored  petals.  The  bractlets  are  linear 
and  the  fruit  consists  of  15  to  20  indehiscent  carpels.  The  root 
is  used  in  medicine  as  a  demulcent. 
39 


610  A  TEXT-BOOK  OF  BOTANY. 

GOSSYPIUM  species. — The  plants  are  herbs  or  shrubs  with 
3-  to  5-lobed  leaves,  and  large  axillary  flowers;  the  fruit  is  a 
5-locular,  dehiscent  capsule  or  pod ;  the  seeds  are  spherical  or 
somewhat  angular  and  covered  with  long  i -celled  hairs,  which] 
latter  constitute  cotton- (Fig.  139). 


FIG.  335.  Indian  mallow,  velvet  leaf  (Abulilon  Theophrasti).  A  common  plant  grow- 
ing in  waste  places,  with  velvety,  heart-shaped  leaves;  yellow  flowers;  and  characteristic 
fruits,  consisting  of  12  to  15  beaked  carpels. — After  Brown. 

There  are  three  important  cultivated  species.  ( i )  SEA  ISLAND 
COTTON  is  obtained  from  Gossypium  barbadense,  a  plant  which  is 
principally  cultivated  in  the  Southern  United  States  and  also  in 
Northern  Africa,  Brazil,  Peru  and  Queensland.  This  species  is 
distinguished  by  the  fact  that  after  removal  of  the  hairs  from 


CLASSIFICATION  OF  ANGIOSPERMS.  611 

the  seeds  they  are  smooth.  (2)  G.  arboreum  has  purplish-red 
flowers,  yields  a  particularly  white  cotton,  and  is  cultivated  in 
Egypt,  Arabia  and  India.  (3)  G.  herbaceum  is  distinguished  by 
its  broadly  lobed  leaves  and  yellowish  flowers.  This  plant  has 
been  cultivated  for  over  26  centuries  in  Arabia  and  the  East 
Indies,  and  since  1774  in  the  United  States.  Of  this  latter  species 
there  are  a  number  of  cultivated  varieties.  The  bark  of  the  root 
constitutes  the  cotton-root  bark  of  medicine. 

The  seeds  of  the  genus  Gossypium  contain  a  large  percentage 
of  fixed  oil,  which  is  obtained  by  expression  and  is  official  as 
COTTON  SEED  OIL.  The  residue  is  known  as  cotton  seed  oil-cake, 
and  contains  a  considerable  amount  of  proteins  with  a  small  quan- 
tity of  oil  and  a  poisonous  principle,  ricin.  A  fat  resembling  .that 
of  Cacao  is  obtained  from  the  seeds  of  Pachira  macrocarpa  of 
Brazil ;  Kapak  oil  is  derived  from  the  seeds  of  Eriodendron  anfrac- 
tuosum  caribccum  of  the  West  Indies. 

The  flowers  of  some  of  the  members  of  the  Malvaceae  contain 
coloring  principles,  and  have  been  used  for  dyeing,  as  Hollyhock 
(Althaa  rosea)  and  Mallow  (Malva  sylvestris).  MUSK  SEED  or 
Amber  seed,  which  is  used  in  perfumery  as  a  substitute  for  musk, 
is  obtained  from  Abelmoschus  moschatus  indigenous  to  the  East 
Indies  and  now  cultivated  in  other  tropical  countries.  Malva  mos- 
chata  also  has  the  odor  of  musk,  and  is  found  in  Middle  and 
Southern  Europe. 

Saponin  is  found  in  the  roots  of  Sida  jamaicensis  and  Hibiscus 
Sabdariffa  of  the  East  and  West  Indies ;  Sida  paniculata  of  Peru 
is  used  as  an  anthelmintic  and  the  action  is  supposed  to  be  due 
to  the  glandular  hairs.  The  seeds  of  several  members  of  this 
family  are  used  as  substitutes  for  coffee,  as  Abutilon  muticum  of 
Egypt,  and  Okra  or  Gumbo  (Hibiscus  esculentus).  The  leaves 
of  Sida  canariemis  and  5\  retusa,  the  latter  of  India,  have  been 
substituted  for  tea  leaves.  The  fruits  of  several  of  the  members 
of  this  family  are  edible,  as  Hibiscus  esculentus,  which  yields  the 
vegetable  okra,  and  H.  ficulneus  of  Ceylon  and  Egypt,  which  are 
used  like  beans. 

Fibers  are  obtained  from  a  number  of  the  other  members  of 
this  family,  as  the  bast  fibers  of  Hibiscus  tiliaceus  of  the  Tropics, 
H.  cannabinus  of  the  East  Indies,  Urena  lobata,  Abutilon  indicum, 


j6i2  A  TEXT-BOOK  OF  BOTANY. 

Sida  retusa,  and  Napcca  Iccvis,  all  cultivated  more  or  less  in  tropical 
countries. 

d.  FAMILY   BOMBACE/E.— This   is   a   group   of   tropical 
trees  yielding  a  variety  of  useful  products.     A  gum  is  obtained 
from  Bombax  malabaricum,  and  mucilage  is  contained  in  the  genus 
Ochroma  and  several  species  of  Bombax.     The  root  of  Bombax 
malabaricum  contains  tannin  in  addition.     The  bast  fibers  of  a 
number  of  the  plants  of  this  family  are  used  like  cotton  in  making 
fabrics,  as  species  of  Bombax,   Chorisia  and  Adansonia.     The 
fruits  of  several  of  the  Bombacese  contain  tartaric  acid,  as  the 
Sour  Cucumber  tree  or  CREAM-OF-TARTAR  TREE  (Adansonia  Greg- 
orii)   of   Northern  Australia;  and  the  MONKEY-BREAD  TREE  or 
BAOBAB  (Adansonia  digitata)  of  India  and  South  America,  which 
attains  a  diameter  of  9  M.     The  green  fruit  of  Matisia  cordata 
of  the  Andes  region  is  edible.    The  seeds  of  Bombax  insigne  and 
Matisia  Castano  of  South  America  yield  a  product  on  roasting 
which  is  used  like  cacao  bean.    The  seeds  of  Cavanillesia  umbel- 
lata  of  Peru  are  edible  and  contain  a  considerable  quantity  of 
fixed  oil. 

e.  STERCULIACE^:   OR   COLA    FAMILY.— The   plants 
are  herbs,  shrubs  or  trees,  sometimes  lianes,  with  mostly  simple, 
petiolate,   alternate   leaves ;   the  flowers   are   small   and    form   a 
rather  complex  inflorescence. 

Theobroma  Cacao  is  a  small  tree  5  to  10  M.  high,  with  cori- 
aceous, glaucous,  entire  leaves,  and  clusters  of  brownish  5-mer- 
ous  flowers  arising  from  the  older  branches  or  stem ;  the  fruit  is 
large,  fleshy,  ovoid,  10- furrowed  longitudinally,  yellow  or  reddish, 
and  contains  five  rows  of  seeds,  10  or  12  in  each  row  (Fig.  336). 
The  seeds  are  ovoid,  somewhat  flattened,  and  with  large,  convo- 
luted cotyledons  which  break  up  into  more  or  less  angular  frag- 
ments on  drying.  The  seeds  contain  35  to  50  per  cent,  of  a  fixed 
oil  known  as  CACAO  BUTTER  and  official  as  Oleum  Theobromatis ; 
15  per  cent,  of  starch;  15  per  cent,  of  proteins;  I  to  4  per  cent, 
of  theobromine;  0.07  to  0.36  per  cent,  of  caffeine,  about  0.5  per 
cent,  of  sugar,  and  also  a  small  amount  of  tannin.  The  red  color 
of  the  seed  is  due  to  a  principle  known  as  cacao-red  which  is 
formed  by  the  action  of  a  ferment  on  a  glucoside. 

The  Cacao  tree  is  indigenous  to  the  countries  bordering  the 
Gulf  of  Mexico  and  is  now  cultivated  in  many  tropical  countries. 


CLASSIFICATION  OF  ANGIOSPERMS. 


613 


FIG.  336.  Cacao  tree  (Theobroma  Cacao),  growing  in  Rio  Hondo,  Costa  Rica.  In 
the  illustration  is  shown  the  peculiar  habit  of  this  tree  in  producing  large,  ovoid,  fleshy 
fruits  on  the  main  axis  or  trunk,  as  well  as  on  the  older  branches.  When  Cortez  conquered 
Mexico  he  found  the  Aztecs  using  Cacao  seeds  to  make  a  beverage;  this  was  later  introduced 
into  Europe,  previous  to  either  coffee  or  tea. — Reproduced  by  permission  of  The  Phila- 
delphia Commercial  Museum. 


614 


A  TEXT-BOOK  OF  BOTANY. 


FlG.  337.  A  flowering  branch  of  the  Kola  nut  tree  (Cola  acuminata),  growing  in  Trini- 
dad. The  leaves  are  obovate  or  lanceolate,  acuminate,  and  in  the  axils  are  borne  small 
clusters  of  purplish  flowers.  The  tree  is  indigenous  to  Africa  and  is  extensively  cultivated 
in  the  West  Indies  and  Brazil,  in  which  countries  it  has  become  naturalized. — Reproduced 
by  permission  of  The  Philadelphia  Commercial  Museum. 


CLASSIFICATION  OF  ANGIOSPERMS.  615 

Most  of  the  cacao  of  the  market  is  obtained  from  Ecuador  (the 
Guayaquil  variety  being  especially  valued),  Curasao,  Mexico, 
Trinidad,  and  the  Philippine  Islands.  The  seeds  of  the  wild 
plants  contain  a  bitter  principle,  the  quantity  of  which  is  found 
to  be  greatly  reduced  in  the  plants  when  under  cultivation.  The 
bitter  principles  in  the  raw  product  are  more  or  less  destroyed 
by  the  process  of  fermentation  to  which  the  seeds  are  subjected 
in  preparing  them  for  use,  which  at  the  same  time  develops  the 
aroma. 

Cola  acuminata  is  a  tree  with  lanceolate  or  obovate,  acuminate, 
entire,  petiolate  leaves.  The  flowers  are  purplish,  unisexual,  and 
in  small  axillary  clusters,  frequently  arising  from  the  old  wood ; 
the  fruit  consists  of  five  follicles,  each  containing  4  to  8  seeds. 
The  seed  is  made  up  of  two  large,  fleshy  cotyledons.  They  have 
much  the  same  constituents  as  Cacao,  but  the  proportions  of  these 
differ  (Fig.  337).  The  leaves  of  Waltheri'a  glomerate,  are  used 
as  a  hemostatic  in  Panama  like  matico,  as  are  also  the  leaves  of 
Pterospermum  acerifoliuvn.  The  inner  bark  of  Fremontia 
calif ornica  is  used  for  purposes  similar  to  those  of  elm  bark. 
Mucilage  is  also  found  in  the  following  genera :  Pentapetes,  Wal- 
theria,  Guazuma,  Relict eres,  and  Sterculia.  Tannin  is  found  in 
the  bark  of  Guazuma  uhnifolia  of  South  America.  An  oil  is  manu- 
factured from  the  seeds  of  Sterculia  fcctida  of  the  East  Indies 
and  Cochin  China.  The  seeds  of  a  number  of  species  of  Sterculia 
are  edible.  Abronia  angusta  of  India  yields  a  fiber  which  has 
been  suggested  as  a  substitute  for  silk. 

XIX.    ORDER    PARIETALES. 

This  is  a  group  of  plants  of  rather  wide  distribution,  and 
includes  perennial  herbs  like  the  violets;  evergreen  shrubs,  such 
as  the  Tea  Plant ;  and  vines  like  the  Passion  flower.  As  the  name 
indicates,  the  plants  of  this  order  are  characterized  by  the  flowers 
having,  for  the  most  part,  ovaries  with  parietal  placentas. 

a.  FAMILY  DILLENIACE^.— The  plants  are  mostly  trop- 
ical trees  which  yield  valuable  timber.  The  wood  of  a  species  of 
Dillenia  growing  in  the  East  Indies  also  contains  red  coloring 
substances.  The  fruits  of  Dillenia  indica  contain  citric  acid  and 
are  used  like  lemons.  The  leaves  of  Curatella  americana  contain 
considerable  silicon  and  are  used  to  polish  wood.  Dillenia  speciosa 


6i6 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  338.  Leaves,  flowers,  and  fruits  of  the  Tea  plant  (Thea  sinenis,  or  Camellia 
viridis).  The  plant  is  a  shrub  or  small  tree  bearing  lanceolate,  evergreen  leaves,  and  in 
the  axils  occur  the  rather  large,  white,  fragrant  flowers.  The  fruits  are  small,  globular 
capsules. — Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

of  India  contains  a  large  percentage  of  tannin.  Some  species  of 
Dillenia  are  cultivated  and  the  foliage  and  flowers  combine  to 
make  the  plants  the  most  beautiful  in  the  plant  kingdom. 

b.  MARCGRAVIACE;E.— The  members  of  this  family  are 


CLASSIFICATION  OF  ANGIOSPERMS.  617 

partly  epiphytic,  and  have  dimorphic  leaves,  the  smaller  ones  being 
pitcher-like.  The  plant  which  is  cultivated  in  greenhouses,  Marc- 
gravia  uinbellata,  is  used  in  the  Antilles  in  medicine. 

c.  THEACE;E  OR  TEA  FAMILY.— The  plants  are  shrubs 

or  trees  with  alternate,  evergreen  leaves,  and  perfect,   regular 


FIG.  339.  Picking  tea  on  a  plantation  in  Japan,  the  wall  at  the  left  probably  being 
the  ruins  of  an  ancient  temple.  While  the  plant  ordinarily  is  a  shrub,  it  is  kept  trimmed 
and  is  a  bush  from  2  to  5  feet  high.  The  plants  begin  to  bear  in  the  third  year,  and  continue 
to  yield  a  commercial  article  from  3  to  7  years  thereafter.  The  number  of  crops  per  year 
is  determined  by  the  geographical  location.  In  the  tropical  fields  of  Ceylon,  India,  and 
Japan  leaves  are  picked  frequently,  while  in  northern  Japan  they  secure  only  one  crop  a 
year. — Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

flowers  with  numerous  stamens,  occurring  one  or  more  in  the 
axils  of  the  leaves.  The  fruit  is  a  3-  to  5-locular,  dehiscent 
capsule.  The  most  important  member  of  this  family  is  Thca 
sinensis,  the  two  varieties  viridis  and  Bohea  furnishing  the  leaves 
known  as  TEA.  The  Tea  tree  is  indigenous  to  Eastern  Asia,  and  is 
now  extensively  cultivated  in  China,  Japan,  India,  Java,  Brazil, 
Sicily,  Portugal  and  France,  and  to  some  extent  in  the  Southern 
United  States  (Figs.  338,  339). 


618  A  TEXT-BOOK  OF  BOTANY. 

The  fresh  leaves  of  Thea  do  not  have  the  properties  which 
characterize  the  commercial  article,  the  aroma  and  other  qualities 
being  developed  after  special  treatment.  Two  general  classes  of 
tea  are  found  in  commerce,  these  depending  on  the  mode  of  treat- 
ment. Those  which  are  rapidly  dried  by  means  of  artificial  heat 
constitute  GREEN  TEA.  The  leaves  which  are  slowly  dried,  per- 
mitting fermentation  to  set  in,  furnish  BLACK  TEA.  Tea  leaves 
contain  1.5  to  3.5  per  cent,  of  caffeine;  theobromine  and  the- 
ophylline  (an  isomer  of  theobromine)  ;  10  to  20  per  cent,  of  gallo- 
tannic  acid ;  quercitrin,  and  a  volatile  oil  containing,  among  other 
components,  methyl  salicylate.  The  seeds  contain  about  30  per 
cent,  of  fixed  oil,  I  per  cent,  of  caffeine,  and  saponin.  The  leaves 
furnish  one  of  the  sources  of  the  official  caffeine.  Saponin  is 
found  in  the  seeds  of  Thea  Sasanqua  of  China  and  Japan.  Two 
saponin-like  substances  (assamin  and  assaminic  acid)  are  found 
in  the  seeds  of  Thea  assamica.  The  flowers  of  T.  Sasanqua  are 
used  in  China  and  Japan  to  flavor  teas.  The  flowers  and  leaves 
of  Thea  kissi  are  used  as  an  insecticide.  The  red  colored  sap  of 
Laplacea  Hcematoxylon  of  New  Granada  is  used  in  medicine. 

d.  GUTTIFER^  OR  GAMBOGE  FAMILY.— The  plants 
are  principally  shrubs  and  trees  of  the  Tropics,  that  is,  if  we 
exclude  the  Hypericaceae  which  are  now  put  in  a  group  by  them- 
selves. 

Garcinia  Hanburyi  is  a  tree  with  ovate,  petiolate,  coriaceous, 
opposite  leaves.  The  flowers  are  small,  yellow,  dioecious,  occur- 
ring in  small  clusters  in  the  axils  of  the  leaves.  The  fruit  is  a 
pome-like  berry,  with  a  papery  endocarp  and  an  oily  sarcocarp, 
and  3  or  4  seeds,  i  in  each  loculus  (Fig.  340).  The  trees  are 
chiefly  valued  on  account  of  the  gum-resin  known  as  gamboge 
which  they  contain. 

A  resin  used  in  making  plasters  is  obtained  from  Calophyllum 
brasiliense  of  Brazil.  Balsams  resembling  Copaiba  have  been 
obtained  from  Calophyllum  Calaba  of  the  West  Indies.  Balsams 
known  as  TACAMAHAC  are  also  derived  from  the  following  plants : 
Bourbon  Tacamahac  from  Calophyllum  Tacamahaca,  India  Taca- 
mahac  from  C.  apetalum  and  Brazilian  Tacamahac  from  Rheedia 
Madruno.  Balsams  are  also  obtained  from  Caraipa  grandiflora 


CLASSIFICATION  OF  ANGIOSPERMS. 


619 


of  Brazil,  and  Rheedia  acuminata  of  Peru.     Resins  and  balsams 
are  obtained  from  a  number  of  species  of  Clusia. 

A  yellow  coloring  principle,  mangostin,  is  obtained  from  the 
bark  and  fruit  of  Mangosteen  (Garcinia  Mangostana)  of  the  East 
Indies.  Yellow  coloring  principles  are  found  in  Ochrocarpos 


FIG.  340.    Gamboge    plant    (Garcinia   Hanburyi).      A   branch   showing  the 
axillary  pistillate  flowers  and  pome-like  fruits. — After  Baillon. 

longifolius  of  India  and  Vismia  acuminata  of  South  America. 
Tannin  occurs  in  Mahurea  palustris  of.  Brazil,  Mesua  ferrea  of 
the  East  Indies,  that  flower-buds  of  Ochrocarpos  longifolius  of 
India,  and  several  species  of  Cratoxylum  of  China  and  Java. 

A  butter-like  fat  is  obtained  from  the  seeds  of  Garcinia  indica. 
A  fixed  oil  known  as  LAUREL-NUT  OIL  is  derived  from  the  seeds 
of  Calophyllum  Inophyllum  and  other  species  of  Calophyllum 


620  A  TEXT-BOOK  OF  BOTANY. 

growing  in  the  East  Indies,  Cochin  China  and  Brazil,  as  well  as 
the  seeds  of  Symphonia  fasciculata  of  Brazil. 

The  bark  of  Clusia  pseudochina  is  used  in  Peru  as  a  substi- 
tute for  cinchona.  An  alkaloid  is  found  in  Visinia  robusta  of  Java. 
A  gum  is  obtained  from  Calophyllutn  tomentosum  of  India  and 
Vismia  acunrinata,  that  of  the  latter  being  purgative.  The  flower 
buds  of  the  India  Suringi  (Ochrocarpos  longifolius)  have  an 
aromatic  odor  resembling  cloves.  Aromatic  principles  are  also 
found  in  other  plants  of  this  family. 

Edible  fruits  are  yielded  by  the  following  plants :  MANGO 
FRUIT  from  Garcinia  Mangostana  and  other  species  of  Garcinia; 
MAMMEI  APPLE  or  Apricot  of  St.  Domingo  from  Mammea  anier- 
icana  of  tropical  America,  the  latter  being  used  in  the  prepara- 
tion of  Mammey  wine  or  "  Toddy  "  and  a  liquor  known  as  "  Eau 
de  Creole."  The  seeds  of  Platonia  insignis  are  used  like  almonds 
in  Brazil  and  Paraguay ;  the  fruit  of  the  latter  plant  is  quite  acid 
and  is  eaten  with  sugar. 

e.  HYPERICACE^:  OR  ST.  JOHN'S-WORT  FAMILY.— 
The  plants  are  herbs  or  shrubs  of  the  temperate  regions,  and  are 
represented  in  the  United  States  by  the  Hypericums,  which  are 
quite  common.  The  flowers  are  characterized  by  the  numerous 
stamens  which  are  united  into  distinct  groups  or  clusters.  The 
flowers  of  Hypericum  perforatum  or  Common  St.  John's-wort 
contain  yellow  and  red  coloring  principles.  Yellow  coloring  prin- 
ciples have  also  been  isolated  from  Hypericum  larici folium  of 
Ecuador  and  H.  elodes  of  Northern  Europe.  The  entire  plant  of 
H.  perforatum  is  used  in  medicine  and  contains  considerable  resin, 
and  a  small  amount  of  volatile  oil. 

/.  FAMILY  DIPTEROCARPACE^:.— The  plants  of  this 
family  are  principally  trees  and  indigenous  to  tropical  Asia.  The 
family  derives  its  name  from  the  winged  fruits  of  the  principal 
genus  Dipterocarpus.  A  number  of  economic  products  are  fur- 
nished by  this  group  of  plants.  BORNEO  CAMPHOR  is  obtained 
from  Dryobalanops  aromatica.  The  camphor  separates  in  canals 
in  the  older  parts  of  the  wood  and  between  the  wood  and  bark, 
and  is  obtained  by  felling  the  trees,  splitting  the  wood,  and  then 
removing  the  camphor  by  hand.  Owing  to  the  fact  that  some  of 
the  trees  do  not  contain  camphor,  it  is  sometimes  necessary  to  fell 


.       CLASSIFICATION  OF  ANGIOSPERMS.  621 

a  hundred  trees  in  order  to  obtain  6  or  8  K.  of  the  product.  The 
young  twigs  of  this  plant  as  well  as  the  older  wood  yield  a  volatile 
oil  known  as  Oil  of  Borneo  camphor. 

GURJUN  BALSAM  or  Wood  oil  is  obtained  from  a  number  of 
species  of  Dipterocarpus  growing  in  the  East  Indies  by  incising 
the  stems  as  in  the  collection  of  turpentine.  The  balsam  is  used 
as  a  substitute  for  copaiba  and  contains  an  ethereal  oil  which 
consists  chiefly  of  a  sesquiterpene,  an  indifferent  resin,  and  gur- 
junic  acid.  SINDOR  BALSAM  is  obtained  from  Dipterocarpus  mar- 
ginatus  of  Borneo.  A  resin  known  as  "  PINEY  RESIN,"  which  is 
used  as  a  substitute  for  Dammar,  is  obtained  from  a  number  of 
species  of  Vateria  growing  in  India.  CHAIA  RESIN  is  obtained 
from  Shorea  rubifolia  of  Cochin  China.  The  bark  of  Shorea 
robusta  of  Northern  India  contains  32  per  cent,  of  tannin.  The 
seeds  of  species  of  Shorea,  Pinanga,  Gysbertsiana  and  Isoptera 
yield  the  fatty  oil  known  in  Java  as  TANGKAWANG.  The  seeds  of 
a  number  of  plants  of  this  family  contain  considerable  starch,  as 
Vateria,  Vatica  and  Doona.  The  woods  of  the  following  genera 
are  extensively  used :  Vatica,  Shorea,  and  Hopea. 

g.  FAMILY  TAMARICACE^E.— The  plants  are  halophytic 
shrubs  found  in  the  desert  regions  of  Central  Asia  and  Mediter- 
ranean countries  and  one  genus  (Fouquieria)  is  found  in  Mexico. 
Fouquieria  splendens  is  cultivated  to  some  extent,  and  is  known 
as  Ocotilla  or  Coach-whip  Cactus.  The  bark  contains  gum,  resin 
and  wax;  the  latter  is  known  as  OCOTILLA  WAX  and  resembles 
beeswax.  The  twigs  of  Myricaria  germanica  of  Europe  are  used 
as  a  substitute  for  hops.  A  manna-like  sugar  is  formed  on  the 
stems  of  Tamarix  mannifera  growing  in  Egypt,  Arabia  and 
Afghanistan,  as  the  result  of  the  sting  of  an  insect  (Coccus  manni- 
parus).  Tannin  is  found  in  a  number  of  species  of  Tamarix  as 
well  as  in  the  galls  formed  on  the  plants,  the  tannin  being  used 
for  dyeing.  A  table  salt  is  prepared  from  the  ash  of  several 
species  of  Reaumuria  found  in  Northern  Africa  and  the  East 
Mediterranean  region. 

h.  FAMILY  BIXACE;E.— These  are  shrubs  or  trees  found 
in  the  Tropics,  and  are  of  interest  chiefly  on  account  of  the  seeds 
of  Bixa  Orellana  which  furnish  the  coloring  matter  known  as 
ANNATTO  (Orlean,  Arnotta).  The  plant  is  found  in  tropical 


622  A  TEXT-BOOK  OF  BOTANY. 

America  and  also  in  Polynesia  and  Madagascar.  The  seeds  are 
covered  with  a  fleshy  arillus  from  which  the  coloring  matter  is 
prepared  by  means  of  water.  The  insoluble  matter  is  collected, 
made  into  cakes  and  chiefly  used  for  dyeing  and  coloring.  Annatto 
contains  a  red  crystalline  principle,  bixin,  a  yellow  coloring  prin- 
ciple, orellin,  and  an  ethereal  oil.  The  root  of  this  plant  also  con- 
tains some  coloring  matter.  A  yellow  coloring  principle  is  found  in 
Cochlospermum  tinctorium  of  Senegambia  and  an  aromatic  resin  is 
obtained  from  Cochlospermum  Gossypium  of  Ceylon  and  Malabar. 

i.  FAMILY  CANELLACE^:  OR  WINTER  AN  ACE^.— 
These  are  trees  with  aromatic  barks  having  an  odor  of  cinnamon ; 
pellucid-punctate  leaves;  and  golden-yellow  flowers.  The  most 
important  member  of  this  family  is  Winterania  Canella  growing  in 
the  Antilles  and  in  Southern  Florida,  which  furnishes  the  CANELLA 
BARK  or  False  Winter's  bark  used  in  medicine.  The  bark  occurs 
in  large  quills  or  broken  pieces,  from  3  to  10  mm.  thick,  with  the 
periderm  nearly  entirely  removed,  the  outer  surface  yellowish  or 
orange-red  with  transversely  elongated  patches  of  cork  and  shal- 
low, whitish  depressions ;  the  fracture  is  short  with  numerous  resin 
canals ;  the  odor  aromatic ;  taste  aromatic,  bitter  and  pungent.  It 
contains  mannitol,  resin  and  0.5  to  1.28  per  cent,  of  a  volatile  oil 
containing  eugenol,  cineol,  caryophyllene  and  pinene.  The  bark 
of  one  or  more  species  of  Cinnamodendron  of  tropical  America  is 
sometimes  substituted  for  Canella  bark,  but  it  is  distinguished  by 
containing  tannin,  which  constituent  is  not  found  in  Canella. 

;.  VIOLACE^:  OR  VIOLET  FAMILY.— The  plants  are 
herbs  or  shrubs  with  basal  or  alternate  leaves,  perfect,  irregular 
flowers,  and  3-valved  dehiscent  capsules  (Fig.  280,  /).  The  best 
known  representatives  of  this  group  are  the  cultivated  species  of 
the  genus  Viola,  including  the  English  or  sweet  violet  ( Viola  odor- 
ata),  which  produces  a  volatile  oil  containing  ionon ;  and  the  varie- 
ties of  Viola  tricolor  vulgaris  which  furnish  the  pansies  of  the 
garden.  The  entire  herb  of  Viola  tricolor  has  been  used  in  medi- 
cine and  contains  the  yellow  coloring  principle  viola-quercitrin, 
salicylic  acid  and  methyl  salicylate  (Figs.  201,  232). 

k.  FAMILY  FLACOURTIACE^:.  —  These  are  tropical 
shrubs  and  trees,  and  are  chiefly  of  interest  because  of  their  valu- 
able woods  and  acid,  juicy  fruits.  A  number  of  them  are  of 


CLASSIFICATION  OF  ANGIOSPERMS.  623 

medicinal  interest.  CHAULMUGRA  OIL  is  said  to  be  obtained  from 
the  seeds  of  Gynocardia  odorata  of  Farther  India.  The  seeds  also 
contain  gynocardic  acid  and  hydrocyanic  acid.  The  latter  is  also 
present  in  the  seeds  of  Hydnocarpus  venenata  of  Southern  India 
and  Ceylon  and  the  leaves  of  Kiggelaria  africana. 

A  number  of  species  of  Lcetia  growing  in  Cuba  yield  a  resin 
resembling  sandarac.  The  Coccos  oil  which  is  used  in  perfumery 
is  obtained  from  several  species  of  Myroxylon  growing  in  Poly- 
nesia. The  fixed  oils  from  the  seeds  of  Gynocardia  odorata  and  of 
several  species  of  Pangium  are  used  in  cooking.  A  bitter  principle 
occurs  in  the  bark  of  Casearia  adstringens  of  Brazil.  A  purgative 
principle  is  found  in  C.  esculenta  of  tropical  Asia  and  Australia. 
The  root  of  Homalium  racemosum  of  Guiana  contains  an  astrin- 
gent principle. 

/.  FAMILY  TURNERACE^.— These  plants  are  herbs, 
shrubs  and  trees  mostly  found  in  tropical  America,  and  are  of 
interest  on  account  of  the  leaves  of  Turnera  diffusa,  particularly 
the  variety  aphrodisiaca,  which  yield  the  DAM  IAN  A  of  medicine 
esteemed  as  a  tonic  laxative  like  Rhamnus  Purshianus.  The  drug 
usually  consists  of  leaves,  although  the  reddish  stems,  yellowish 
flowers  and  globular  capsules  may  be  present.  The  leaves  are 
about  25  mm.  long,  varying  from  oblanceolate  to  obovate;  the 
margin  is  serrate-dentate;  the  color,  light-green  (older  leaves 
somewhat  coriaceous  and  pubescent)  ;  the  odor  aromatic ;  taste 
aromatic  and  bitter.  Damiana  contains  a  volatile  oil,  resin,  and 
the  bitter  principle  damianin.  Ethereal  oils  are  found  in  other 
species  of  Turnera,  and  T.  angustifolia  of  Mexico  contains  con- 
siderable mucilage. 

m.  PASSIFLORACE^  OR  PASSION-FLOWER  FAM- 
ILY.— The  plants  are  mostly  herbaceous  or  woody  vines  climbing 
by  means  of  tendrils,  with  alternate,  palmately-lobed,  petiolate 
leaves  and  solitary,  perfect,  regular  flowers.  The  flowers  are 
peculiar  in  that  between  the  corolla  and  stamens  there  are  numer- 
ous, frequently  petaloid,  colored,  sterile,  filamentous  bodies  which 
are  known  collectively  as  the  "  corona."  The  fruit  is  a  berry  or 
dehiscent  capsule.  The  genus  Passiflora  is  known  as  the  Passion- 
flower because  the  flowers  are  considered  to  be  emblematic  of  the 
Crucifixion,  the  corona  representing  the  crown  of  thorns,  the 


624  A  TEXT-BOOK  OF  BOTANY. 

stamens  the  nails,  and  the  gynaecium  with  its  three  styles,  the 
three  thieves.  The  rhizomes  of  the  Passion-flowers  of  the  South- 
ern States  (Passiflora  incarnata  and  P.  lutea)  have  been  used  in 
medicine.  Not  much  is  known  with  regard  to  the  active  principles 
of  these  two  plants  or  of  the  thirty  other  species  of  Passiflora 
which  are  used  in  medicine.  The  fruits  of  several  species  of  Passi- 
flora are  edible,  and  a  number  of  them  are  cultivated  on  account 
of  their  beautiful  as  well  as  odorous  flowers. 

«.  CARICACE^  OR  PAP  AW  FAMILY.— This  family  is 
composed  of  two  genera  of  latex-containing  trees  growing  in  trop- 
ical America,  the  best  known  of  which  is  the  genus  Carica.  The 
Papaw  or  Melon  tree  (Carica  Papaya)  is  a  small  tree  with  a 
straight,  slender,  usually  unbranched  trunk  which  bears  at  the 
summit  a  cluster  of  long-petiolate,  deeply-lobed  leaves.  The 
flowers  are  dioecious,  and  the  fruit  is  a  large,  melon-like  berry. 
The  green  fruits  as  well  as  the  leaves  contain  a  milk-juice  which 
is  obtained  by  incising  them.  The  material  is  dried  and  is  used 
in  medicine  on  account  of  its  containing  a  proteolytic  ferment, 
papain  or  papayotin,  which  is  active  in  the  presence  of  both  acids 
and  alkalies.  The  leaves  and  fruit  also  contain  the  alkaloid  car- 
paine,  and  in  addition  the  leaves  contain  the  glucoside  carposid. 
The  root  contains  a  glucoside  somewhat  resembling  potassium 
myronate  and  a  ferment  which  has  a  decomposing  action  upon  it. 
A  proteolytic  ferment  is  also  present  in  the  leaves  of  Carica  quer- 
cifolia  of  Argentina.  The  melon  tree  is  cultivated  on  account  of 
the  fruits,  which  are  edible. 

o.  BEGONIACE^:.— This  is  a  family  of  tropical  plants  which 
are  extensively  cultivated.  They  are  herbs  or  shrubs  frequently 
with  tuberous  rhizomes  and  with  characteristic,  asymmetric,  varie- 
gated leaves.  They  are  easily  propagated  by  cuttings,  providing 
they  have  sufficient  moisture,  even  the  leaves  giving  rise  to  new 
plants.  The  roots  of  Begonia  anemonoides  of  South  America  and 
B.  gracilis  of  Mexico  contain  purgative  principles.  Calcium  oxal- 
ate  and  acid  oxalates  are  found  in  the  leaves  of  probably  all  of  the 
species  of  Begonia.  The  roots  of  a  number  of  species  of  this 
genus  are  astringent. 

p.  DATISCACE^E.— The  plants  are  trees  or  shrubs  found 
principally  in  the  Tropics.  A  bitter  principle  is  found  in  the 


CLASSIFICATION  OF  ANGIOSPERMS.  625 

Yellow  hemp  (Datisca  cannabina)  of  Southern  Europe  and  the 
Orient.  The  root  contains  a  yellow  coloring  principle,  datiscin, 
which  is  used  in  the  dyeing  of  silk.  The  wood  of  Octoineles  and 
Tetramelcs  is  used  in  the  making  of  tea-chests. 

XXI.    ORDER    OPUNTIALES. 

The  plants  of  this  order  are  succulent,  with  much  reduced 
leaves,  and  with  flowers  characterized  by  having  a  perianth  with 
numerous  segments  and  an  inferior  ovary. 

a.  CACTACE/E  OR  CACTUS  FAMILY.— This  is  a  remark- 
able family  of  succulent  plants  growing  largely  in  the  arid  regions 
of  Mexico,  Brazil  and  other  parts  of  America.  The  stems  are 
more  or  less  flattened,  terete  or  tuberculated,  in  some  cases  becom- 
ing branched  and  woody.  The  leaves  are  reduced  to  scales,  but 
are  sometimes  larger,  more  or  less  cylindrical  or  dorsiventral,  and 
usually  drop  off  sooner  or  later.  In  the  axils  of  the  leaves  or 
leaf-scars  there  are  usually  groups  of  hairs  and  spines.  The 
flowers  are  mostly  solitary,  sessile,  perfect,  regular  and  conspic- 
uous. The  fruit  is  usually  a  fleshy  berry,  the  fruits  of  a  number 
of  species  being  edible. 

Quite  a  number  of  the  Cacti  have  been  used  in  medicine,  the 
one  most  commonly  employed  being  the  NIGHT-BLOOMING  CEREUS 
(Cereus  grandifiorus) ,  which  is  extensively  cultivated  on  account 
of  its  flowers.  The  flowers  and  fresh  stems  are  the  parts  used. 
They  contain  several  acrid  principles,  including  probably  an  alka- 
loid and  a  glucoside,  the  drug  resembling  in  its  action  digitalis. 

MESCAL  BUTTONS  (Anhalonium)  are  the  dried  tops  of  several 
species  of  Lophophora  growing  in  Northern  Mexico.  The  main 
axis  of  the  plant  is  under  the  ground  and  produces  at  certain 
points  small  aerial  shoots  which  are  more  or  less  button-shaped 
or  disk-like,  being  about  20  to  50  mm.  in  diameter.  In  the  center 
of  the  disk  occur  tufts  of  hairs  which  vary  in  the  different  species, 
and  among  which  are  usually  found  one  or  more  pinkish  flowers. 
The  drug  has  been  used  like  Night-blooming  Cereus,  and  con- 
tains several  alkaloids,  namely,  anhalonine  (similar  to  pellotine), 
mescaline,  anhalonidine  and  lophophorine.  Alkaloidal  principles 
are  also  found  in  other  members  of  this  family. 

The  sap  of  several  species  of  Cereus  of  the  Antilles  has  anthel- 
40 


626 


A  TEXT-BOOK  OF  BOTANY, 


FlG.  341.  Prickly  Pear  or  Indian  Fi'g  (Opuntia  vulgaris),  a  prostrate,  more  or  less 
spreading  cactus,  composed  of  flattened  stems  bearing  very  small,  awl-shaped  and  decidu- 
ous leaves  and  short,  yellowish-green  bristles  and  occasionally  solitary  spines.  The  flowers 
are  pale  yellow,  opening  in  the  sunshine.  The  fruit  is  a  succulent  berry  about  2.5  cm. 
long.  Various  of  these  cacti  are  used  as  food  by  the  cattle,  which  often  eat  them  with  the 
bristles.  Frequently  the  spines  are  burnt  off  by  the  cattlemen  with  the  use  of  gasolene 
torches,  so  as  to  prevent  the  accumulation  of  spines  in  the  stomachs  of  the  cattle  in  the  form 
of  phyto-bezoars,  which  are  globular  accumulations  of  vegetable  tissues.  (See  p.  577.)— 
After  Troth. 


CLASSIFICATION  OF  ANGIOSPERMS.  627 

mintic  properties,  as  also  that  of  certain  species  of  Rhipsalis  and 
Opimtia.  A  caoutchouc-like  exudation  is  obtained  from  Opuntia 
vulgaris  and  other  species  of  Opuntia  growing  in  the  West  Indies. 
An  astringent  principle  is  found  in  the  root  and  bark  of  Opuntia 
Karwinskiana  of  Mexico.  A  tragacanth-like  gum  is  found  in 
Peireskia  Guacamacho  of  Venezuela,  Opuntia  rubescens  of  Brazil 
and  O.  Tuna  of  the  West  Indies,  Mexico  and  South  America.  An 
alcoholic  beverage  is  made  by  the  Indians  of  Sonora  from  the 
fruit- juice  of  Cereus  T lumber gii. 

A  number  of  species  of  Opuntia  yield  edible  fruits.  The 
PRICKLY  PEAR  is  the  fruit  of  Opuntia  Tuna  growing  in  the  West 
Indies  and  tropical  America ;  INDIAN  FIG  is  derived  from  Opuntia 
Ficus-Indica  growing  in  Southern  Europe,  particularly  Sicily ;  a 
fruit  also  known  as  Prickly  pear  or  Indian  fig  is  derived  from 
Opuntia  vulgaris,  a  common  Cactus  growing  in  sandy  soil  in  the 
Eastern  United  States.  The  COCHINEAL  INSECT  which  is  official 
under  the  name  of  coccus  in  a  number  of  pharmacopoeias  (Coccus 
Cacti)  feeds  upon  various  of  the  Cactacea,  more  especially  the 
Nopal  plant,  Nopalea  (Opuntia)  coccinellifera,  a  native  of  Mex- 
ico and  Peru.  (See  Kraemer,  Amer.  Jour.  Pharm.,  1913,  p.  344-) 

XXII.    ORDER    MYRTALES    OR    MYRTIFLOR^. 

The  plants  are  herbs  or  shrubs  with  complete  flowers,  rarely 
apetalous,  producing  one  or  more  ovules  in  each  loculus. 

a.  THYMEL^ACE^:  OR  MEZEREUM  FAMILY.— The 
characters  of  this  family  are  illustrated  by  the  Spurge  laurel  or 
Mezereon  (Daphne  Mezereum),  which  is  a  small  shrub  about  I  M. 
high,  with  oblong-lanceolate,  acute,  entire,  sessile  leaves,  and  small 
groups  of  fragrant  flowers,  the  perianth  tube  of  which  is  purplish- 
red  or  white.  The  fruit  is  an  ovoid,  reddish  drupe.  The  bark  of 
Daphne  Mezereum  and  other  species  of  Daphne  is  used  in 
medicine. 

The  bark  of  Funifera  utilis  of  Brazil  contains  a  vesicating 
principle.  A  principle  with  similar  properties  is  found  in  the 
bark  of  Leather  wood  (Dirca  palustris)  of  the  Eastern  United 
States  and  Canada.  The  fruit  and  leaves  of  Gnidia  carinata  of 
Cape  Colony  contain  emetic  and  drastic  principles.  A  poisonous 
principle  is  found  in  Pimelea  trichostachya  of  Australia.  A 


628  A  TEXT-BOOK  OF  BOTANY. 

yellow  coloring  principle  is  found  in  several  species  of  Daphne 
and  Thymelcua.  The  wood  of  Aquilaria  Agallocha  of  India  and 
China  is  aromatic  and  resembles  the  "  Aloe  wood."  A  balsam  is 
obtained  from  the  wood  of  Pimelea  oleosa  of  Cochin  China.  The 
bast  fibers  of  quite  a  number  of  plants  are  used  in  the  making  of 
paper,  as  of  Daphne  in  India,  Gnidia  of  Madagascar,  Lagetta  (L. 
lintearia  or  Lace-tree)  of  Jamaica  and  St.  Domingo,  Thymelcua 
of  the  Mediterranean  countries  and  Linodendron  of  Cuba.  The 
fibers  of  Leather  wood  (Dirca  palustris)  of  the  Eastern  United 
States  and  Canada  are  said  to  be  used  in  a  similar  manner. 

b.  FAMILY    EL^EAGNACE^.— This    is    a    small    family 
represented  in  the  United  States  by  several  genera,  among  which 
is  the  Buffalo  berry  (Lepargyr&a  argentea),  a  thorny  shrub  found 
in  the  western  part  of  the  United  States  and  the  Northwest  Terri- 
tory.    The  fruit  is  a  reddish  drupe-like  berry  which  contains  a 
small  amount  of  citric  and  malic  acids,  5  per  cent,  of  sugar,  and 
in  composition  is  much  like  the  currant.    It  is  eaten  by  the  Indians, 
and  used  to  a  great  extent  in  the  Western  States  in  the  making 
of  jellies.     The  leaves  and  flowers  of  a  number  of  species  of 
Elaeagnus  are  used  in  medicine. 

c.  LYTHRACE^E    OR    LOOSESTRIFE    FAMILY.— The 
members  of  this  family  are  herbs,  shrubs  and  trees  usually  with 
opposite,  entire  leaves.    The  flowers  are  in  racemes  and  the  fruit 
is  a  capsule.    Quite  a  number  of  the  plants  yield  valuable  woods 
and  a  number  are  cultivated  as  ornamental  plants. 

The  flowers  of  Woodfordia  floribunda  of  India  contain  a  red 
coloring  principle,  and  the  bark  and  leaves  of  Lafccnsia  Pacari  of 
Brazil  contain  a  yellow  coloring  principle.  Considerable  tannin 
is  found  in  the  root  of  the  Purple  loosestrife  (Ly thrum  Salicaria) 
of  the  Northern  United  States  and  Canada,  and  widely  distrib- 
uted in  the  Old  World ;  and  also  in  the  fruit  of  Woodfordia  flori- 
bunda,  a  plant  which  is  extensively  cultivated  in  greenhouses.  A 
bitter  principle,  nessin,  is  found  in  the  leaves  of  Nescea  syphilitica 
of  Mexico  and  probably  other  species  of  this  genus.  Cuphea 
viscosissima  of  Mexico  is  said  to.  resemble  digitalis  in  its  physiologi- 
cal action.  A  vesicating  principle,  resembling  cantharidin  in  its 
action,  is  obtained  from  the  fresh  leaves  of  Ammannia  baccifera 
of  India.  A  narcotic  principle  is  found  in  the  seeds  of  Lager- 


CLASSIFICATION  OF  ANGIOSPERMS.  629 

strccmia  Flos-regina  of  India.  The  flowers  of  Lawsonia  inermis, 
native  to  and  cultivated  in  the  Orient,  have  an  odor  resembling  that 
of  the  Tea  rose.  The  shrub  is  also  cultivated  to  some  extent  in 
the  West  Indies  and  is  known  in  the  Orient  as  the  HENNA  PLANT. 
The  leaves  are  used  in  the  preparation  of  the  cosmetic  Hinna. 
They  contain  an  orange  or  brownish-yellow  dye  which  is  used  in 
the  dyeing  of  the  skin  and  hair. 

d.  PUNICACE^:  OR  POMEGRANATE  FAMILY  includes 
a  single  genus  of  two  species.    The  Pomegranate  (Punica  grana- 
tum)  indigenous  to  the  Levant  and  now  extensively  cultivated  is 
of  chief  interest.    The  plants  are  small  trees,  the  young  twigs  of 
which  are  4-angled  and  frequently  thorn-like.     The  leaves  are 
opposite,  ovate-lanceolate,  entire  and  short-petiolate.    The  torus, 
calyx  and  corolla  are  scarlet,  and  the  gynsecium  consists  of  two 
whorls  of  carpels.    The  fruit  is  an  inferior  edible  berry  with  a  hard 
pericarp  or  rind.     The  pulpy  portion  is  formed  from  the  outer 
layer  of  the  seed-coat.    The  bark  of  the  root  and  stem  is  used  in 
medicine  (see  Granatum,  Vol.  II).    The  rind  of  the  fruit  is  used  as 
an  astringent  because  of  the  tannin  which  it  contains.    It  does  not 
appear,  however,  to  contain  the  alkaloids  found  in  the  official  bark. 

e.  FAMILY   LECYTHIDACE^.— The    plants    are    mostly 
shrubs  and  trees  indigenous  to  the  Tropics.     They  are  of  chief 
interest  on  account  of  the  BRAZIL-NUT  (Fig.  342)  obtained  from 
Bertholletia  excelsa,  and   the   Sapucaya-nut  obtained   from  the 
Monkey-pot  tree  (one  or  more  species  of  Lecythis),  both  genera 
of  South  America.     The  seeds   (so-called  nuts)   are  rich  in  oil 
and  proteins  and  are  edible.    The  fruit  of  Careya  arborea  is  drupa- 
ceous and  is  also  edible,  the  seeds  being  considered,  however, 
to  be  poisonous.     Bitter  narcotic  or  poisonous  principles  are  also 
found  in  the  fruit  of  Planchonia  valida  of  the  Molucca  Islands  and 
the  seeds  of  a  number  of  species  of  Lecythis.    The  fruits  and  roots 
of  a  number  of  species  of  Barringtonia  are  used  in  China  and  Java 
to  stupefy  fish.     The  pericarp  of  the  fruit  of  Fcetida  moschata 
of  Guiana  contains  considerable  quantities  of  an  ethereal  oil.    The 
flowers  of  Grids  cauMora  of  the  Antilles  are  used  like  tea.     A 
cooling  drink  is  made  from  the  sarcocarp  of  Couroupita  guianensis 
of  the  West  Indies  and  Guiana 


630 


A  TEXT-BOOK  OF  BOTANY, 


/.  RHIZOPHORACEyE  OR  MANGROVE  FAMILY.— 
These  are  tropical  shrubs  or  small  trees  with  evergreen,  cori- 
aceous leaves,  small  cymose  and  axillary  flowers,  and  seeds  which 
germinate  while  the  fruit  is  still  attached  to  the  plant.  The  best 


FIG.  342.  Brazil-nut  (also  known  as  Para  nut,  cream  nut,  and  nigger-toe),  the  seeds 
of  Bertholletia  excelsa,  a  Brazilian  tree  belonging  to  the  Fam.  Myrtaceae.  In  the  illustration 
is  shown  a  portion  of  the  fruiting  branch  with  some  of  the  long,  leathery  leaves.  The  fruits 
terminating  the  branches  are  woody,  vary  from  10  to  15  cm.  in  diameter,  and  are  in  the 
nature  of  a  pyxis, — i.e.,  opening  by  means  of  a  lid.  It  encloses  about  20  brownish-gray, 
3-sided  seeds,  which  are  largely  exported  from  Para. — Reproduced  by  permission  of  The 
Philadelphia  Commercial  Museum. 

known  genus  of  this  family  is  Rhizophora  (Mangrove  tree),  of 
which  there  are  three  species,  the  AMERICAN  MANGROVE  being  R. 
Mangle.  This  tree  produces  aerial  roots  on  the  stems  and  branches, 
and  leaves  which  are  characterized  by  a  number  of  layers  of 


CLASSIFICATION  OF  ANGIOSPERMS.  631 

water-containing  cells.  The  plants  grow  in  muddy  swamps,  or 
along  the  sea-coast  where  the  water  is  brackish,  a  number  together 
forming  the  so-called  "  Mangrove  swamps  "  (Fig.  165). 

The  root  and  bark  of  the  Mangrove,  as  well  as  other  species 
of  Rhizophora  and  several  species  of  Bruguiera,  contain  a  large 
quantity  of  tannin  which  resembles  catechu.  The  aerial  roots  of 
Rhizophora  are  used  by  the  natives  of  Polynesia  in  the  making  of 
bows,  and  the  woods  of  several  genera  are  used  in  carpentry. 

g.  MYRTACE^E  OR  MYRTLE  FAMILY.— This  is  a  group 
chiefly  of  shrubs  and  trees,  some,  as  of  species  of  Eucalyptus, 
being  the  loftiest  trees  known,  attaining  a  height  in  some  instances 
of  105  M.  The  plants  are  indigenous  to  Australia  and  tropical 
America  and  some  are  extensively  cultivated. 

EUCALYPTUS  species. — The  leaves  frequently  vary  in  shape  and 
in  arrangement  on  the  young  and  older  branches  of  the  same 
plant.  On  the  young  branches  they  may  be,  as  in  Eucalyptus 
Globulus,  ovate  or  broadly  elliptical,  opposite  and  sessile,  while 
on  older  branches  they  are  scythe-shaped,  glandular-punctate, 
glabrous,  petiolate  and  alternate.  In  the  latter  case  the  petioles 
are  twisted  and  the  leaves  stand  edgewise  so  that  both  surfaces  are 
equally  exposed  to  the  light  and  hence  of  similar  structure.  The 
flowers  are  solitary,  or  in  cymes  or  umbels,  occurring  in  the  axils 
of  the  leaves.  Petals  are  wanting  and  the  whitish  stamens,  which 
are  numerous  and  inflexed  in  the  bud,  are  covered  by  an  oper- 
culum  or  lid  which  is  considered  to  be  formed  by  the  union  of 
the  sepals,  and  which  dehisces  on  the  maturing  of  the  stamens, 
this  being  one  of  the  most  characteristic  features  of  the  genus. 
The  fruit  is  a  3-  to  6-locular  truncated  capsule  or  pyxis. 

This  is  a  very  important  genus  from  an  economic  point  of 
view,  among  the  products  being  the  volatile  oil  (oil  of  eucalyptus), 
and  eucalyptol,  both  of  which  are  official,  and  the  tannin  or 
so-called  "  gum,"  known  as  Eucalyptus  kino. 

Jambosa  Caryophyllus  (Eugenia  caryophyllata). — This  is  a 
small  tree  indigenous  to  the  Molucca  Islands  and  now  extensively 
cultivated  in  the  Tropics.  The  leaves  are  opposite,  ovate-lance- 
olate, acuminate,  petiolate,  entire  and  evergreen.  The  flowers  are 
rose-colored  and  in  cymes ;  the  fruit  is  berry-like  and  constitutes 
the  Anthophylli  or  MOTHER-CLOVE.  The  unexpanded  flower-buds 


632  A  TEXT-BOOK  OF  BOTANY. 

constitute  the  drug  or  spice  known  as  Cloves.      (See  Vol.  II.) 

Pimento,  officinatis  is  a  tree  with  opposite,  lanceolate,  acute, 
petiolate,  pellucid-punctate  and  evergreen  leaves.  The  flowers  are 
small,  white  and  in  axillary  racemes.  The  fruit,  known  as  "  All- 
spice," is  used  for  flavoring. 

Not  only  are  ethereal  oils  obtained  from  the  genera  Euca- 
lyptus, Jambosa  and  Pimenta  already  described,  but  also  from 
other  members  of  the  Myrtacese.  OIL  OF  BAY  or  oil  of  Myrcia 
is  distilled  from  the  leaves  of  Pimenta  acris  of  the  West  Indies. 
The  oil  consists  largely  of  eugenol,  methyl-eugenol,  chavicol, 
methyl-chavicol,  citral,  phellandrene  and  myrcene,  and  is  used 
in  the  preparation  of  BAY  RUM.  The  fruits  of  P.  acris  yield  3.3 
per  cent,  of  an  oil  resembling  the  leaf  oil. 

Cheken  leaves  are  obtained  from  Eugenia  Chekan.  They  are 
about  25  mm.  long,  ovate  or  rectangular,  with  entire,  somewhat 
revolute  margin,  light  green,  pellucid-punctate,  aromatic,  astrin- 
gent and  bitter.  Cheken  leaves  yield  about  i  per  cent,  of  a  volatile 
oil  containing  cineol  and  pinene;  4  per  cent,  of  tannin;  a  volatile 
alkaloid  and  a  glucoside. 

Oil  of  Cajeput  is  obtained  from  the  leaves  and  twigs  of  Mela- 
leuca  Leucadendron,  particularly  the  varieties  Cajeputi  and  minor 
of  the  East  Indies.  The  principal  constituents  of  this  oil  are 
cineol,  terpineol,  pinene,  and  a  number  of  aldehydes  and  acid 
esters.  An  oil  resembling  Cajeput  oil  is  obtained  from  the  leaves 
and  flowers  of  Myrceugenia  camphorata  of  Chile. 

The  leaves  of  Myrtus  communis,  a  plant  extensively  cultivated 
in  the  Mediterranean  countries  of  Europe,  yield  a  distillate  with 
water  known  as  EAU  D'ANGE  and  used  as  a  toilet  article. 

The  leaves  of  the  following  plants  are  used  as  substitutes  for 
tea  leaves:  Myrtus  Molina  oi  Chile,  Melaleuca  genistifolia  of 
Australia,  and  Leptospermum  scoparium  and  other  species  of  this 
genus  growing  in  New  Zealand.  The  seeds  of  Eugenia  disticha 
are  known  in  the  Antilles  as  Wild  coffee.  Quite  a  number  of  the 
genera  of  this  family  yield  edible  fruits.  GUAVA  or  Guayava  fruit 
is  obtained  from  Psidium  Guajava  of  tropical  America.  ROSE 
APPLE  is  the  fruit  of  Jambosa  malaccensis,  growing  in  the  East 
Indies  and  Oceanica.  JAMBUSE  BERRIES  are  derived  from  Jambosa 
vulgaris  which  is  extensively  cultivated  in  the  Tropics.  The 


CLASSIFICATION  OF  ANGIOSPERMS.  633 

lemon-like  fruit  of  Myrcia  coriacea  is  used  in  medicine,  the  bark 
in  tanning,  and  the  wood  in  dyeing.  The  fibrous  bark  of  Eugenia 
ligustrina  is  used  like  oakum. 

h.  FAMILY  COMBRETACKE:.— The  members  of  this  fam- 
ily are  shrubs  or  trees,  sometimes  climbing ;  with  usually  alternate, 
petiolate,  simple  leaves ;  sessile  flowers  in  racemes ;  somewhat 
fleshy,  winged,  i-seeded  fruits,  and  are  mostly  found  in  the 
Tropics. 

Like  the  Fagacese  the  plants  of  this  family  contain  a  tannin, 
similar  to  gallotannic  acid,  in  nearly  all  parts  of  the  plant.  The 
MYROBALANS  of  the  East  Indies  are  the  young  fruits  of  Terminalia 
Chebula.  The  pericarp  contains  from  5  to  45  per  cent,  of  tannin, 
the  latter  amount  being  found  in  the  fruits  known  as  Long  or 
Chebula  Myrobalans.  The  fruits  also  contain  ellagic  and  chebu- 
linic  acids.  The  fruits  of  Terminalia  Bellerica  constitute  the  Bel- 
eric  Myrobalans.  The  galls  of  Terminalia  macroptera  of  Africa 
and  other  species  of  Terminalia  as  well  as  of  Bucida  Buceras  of 
tropical  America  are  particularly  rich  in  tannin.  A  yellow  coloring 
principle  is  found  in  Terminalia  Brownii  of  Africa  and  is  used  in 
dyeing  leather.  The  bark  of  T.  Catappa  of  Asia  and  Africa  is  used 
to  dye  leather  black. 

A  gum-resin  with  cathartic  properties  is  obtained  from  Termi- 
nalia fagifolia  of  Brazil.  An  aromatic  resin  is  found  in  Ter- 
minalia angustifolia  of  the  East  Indies.  The  fruits  of  one  or 
more  of  the  Combretacese  are  said  to  be  used  in  the  preparation 
of  the  arrow-poison  of  the  Negritos.  The  seeds  of  Terminalia 
Catappa  and  Combretum  butyrosum  contain  about  50  per  cent. 
of  fixed  oil.  These  seeds  as  well  as  those  of  other  species  of 
Terminalia  and  Quisqualis  indica  of  Farther  India  and  tropical 
Africa  are  edible.  The  seeds  of  the  latter  plant  when  unripe  are 
said  to  be  used  like  mustard.  The  woods  of  a  number  of  the  plants 
of  the  Combretacese  are  valuable  for  building  purposes,  and  some 
of  the  genera  furnish  ornamental  plants  which  are  cultivated  in 
greenhouses. 

i.  FAMILY  MELASTOMATACE^E.— This  is  a  large  family 
of  herbs,  shrubs,  and  trees  with  opposite,  3-  to  Q-nerved  leaves 
and  regular,  perfect,  often  showy  flowers.  They  are  chiefly  found 
in  South  America  and  are  represented  in  temperate  regions  by 


634  A  TEXT-BOOK  OF  BOTANY 

the  Meadow  beauty  (Rhexia).  Quite  a  number  of  the  plants  are 
cultivated  and  a  large  number  yield  edible  fruits.  The  fruits, 
barks  and  leaves  frequently  contain  COLORING  PRINCIPLES.  A  yel- 
low coloring  principle  is  found  in  the  leaves  of  a  number  of  species 
of  Memecylon  of  the  East  Indies  and  Africa,  which  resembles 
that  of  saffron  and  curcuma.  Red  coloring  principles  are  found 
in  the  berries  of  a  number  of  species  of  Blakea  of  South  America. 
A  black  coloring  principle  is  obtained  from  the  fruit  of  several 
species  of  Tamonea  of  tropical  America,  Melastoma  malabathri- 
cum  of  the  East  Indies  and  Tococa  guianensis  of  Northern  South 
America  and  Tibouchina  Maximiliana  of  Brazil.  Tannin  is  found 
in  considerable  quantity  in  the  barks  of  Tibouchina,  Dissotis  and 
Rhynchanthera. 

The  leaves  of  Tamonea  thewzans  are  used  in  Peru  as  a  sub- 
stitute for  tea.  A  mucilage  is  found  in  the  bark  of  Medinilla 
crispata  of  the  Molucca  Islands.  The  flowers  of  the  latter  plant 
as  well  as  of  M.  macrocarpa  are  used  as  a  remedy  for  the  bite  of 
poisonous  serpents. 

;.  ONAGRACE^:  OR  EVENING  PRIMROSE  FAMILY. 
— These  are  mostly  annual  or  perennial  herbs  with  usually  entire 
or  toothed,  simple  leaves.  The  flowers  are  perfect,  regular  or 
irregular,  epigynous,  variously  colored,  solitary  in  the  axils  of  the 
leaves  or  in  somewhat  leafy  spikes.  The  fruit  is  a  dehiscent 
capsule,  berry,  drupe,  or  nut.  This  family  is  represented  in  tem- 
perate regions  by  such  plants  as  the  Willow  herb  (Epilobium), 
Evening  primrose  (QEnothera),  on  which  de  Vries  has  carried  on 
his  famous  mutation  experiments,  and  Enchanter's  nightshade 
(Circsea).  The  cultivated  FUCHSIA  also  belongs  to  this  family. 
A  yellow  coloring  principle  is  obtained  from  the  herb  and  unripe 
fruits  of  Jussieua  pilosa  of  Brazil.  The  roots  of  (Enothera  bien- 
nus,  O.  muricata  and  other  species  of  this  genus  are  edible. 

This  family  also  includes  the  group  of  aquatic  plants,  repre- 
sented by  a  single  genus  and  one  o*f  which,  Trapa  natans  or  Water 
chestnut,  is  naturalized  to  some  extent  in  the  ponds  of  Massachu- 
setts and  New  York.  The  fruit  is  coriaceous,  2-  to  4-spinose,  and 
i -seeded.  The  cotyledons  are  unequal,  rich  in  starch,  and  are 
edible,  sometimes  being  ground  and  made  into  bread  by  the  people 
of  Europe  and  Northern  Asia. 


CLASSIFICATION  OF  ANGIOSPERMS.  635 


FIG.  343.  Evening  Primrose  (CEnothera  biennis),  a  simple,  sometimes  more  or  less 
branching  herb  growing  to  a  height  of  3  to  15  dm.  The  leaves  are  lanceolate  or  oblong- 
lanceolate;  the  flowers  are  symmetrical,  with  yellow  petals;  and  the  capsules  are  narrow 
and  4-valved.  This  plant  is  one  of  the  commonest  of  the  CEnotheras,  growing  in  open  places. 
It  is  a  biennial  like  the  other  species,  but  it  is  possible  for  horticulturists  to  develop  its  life 
history  in  one  year. — After  Brown. 


636  A  TEXT-BOOK  OF  BOTANY. 

XXIII.    ORDER  UMBELLALES  OR  UM  BELLI  FLOR.E. 

The  plants  of  this  order  are  widely  distributed  in  northern 
temperate  regions,  although  there  are  some  representatives  in  the 
Tropics.  The  flowers  are  small,  4-  or  5-merous  and  epigynous. 

a.  ARALIACE^E   OR   GINSENG    FAMILY.— The   plants 
are  mostly  trees  or  shrubs  with  alternate,  petiolate,  simple  or  3-  to 
/-compound  leaves.    The  flowers  are  either  in  umbels  or  panicles. 
The  fruit  is  a  drupe  or  berry.    The  best  known  representatives  of 
this  family  are  the  English  ivy  (Hedera  Helix)  of  Europe,  and 
Ginseng  (Panax  quinque folium)  (Fig.  345)  growing  in  the  East- 
ern and  Central  United  States.     This  plant  is  the  source  of  the 
ginseng  root  of  commerce,  considerable  quantities  of  which  are 
exported  to  China,  where  it  is  used  like  the  root  of  Panax  Ginseng, 
a  plant  growing  wild  in  Manchuria  and  Korea.     Both  plants  are 
also  cultivated  in  the  United  States,  the  roots  from  the  wild  plants 
being  preferred.    The  root  contains  a  volatile  oil,  and  considerable 
starch.    Several  species  of  Aralia  are  used  in  medicine  (Fig.  344). 

The  leaves  of  the  English  ivy  contain  the  glucoside  helixin, 
and  a  carbohydrate,  inosit.  They  also  contain  formic,  oxalic,  malic, 
tannic  and  hederic  acids,  besides  the  yellow  principle  carotin.  The 
fruits  of  the  ivy  contain  a  purplish-red  coloring  substance  and  are 
said  to  be  poisonous. 

The  Chinese  RICE  PAPER  is  made  from  the  pith  of  Tetrapanax 
papyriferum,  which  grows  wild  in  Formosa  and  is  extensively 
cultivated  in  China.  .The  pith  is  cut  spirally  into  thin  strips,  which 
are  spread  out  flat  and  then  cut  into  pieces  varying  from  15  to 
30  cm.  long  and  10  to  12  cm.  broad.  This  paper  differs  from 
other  papers  in  that  it  is  a  natural  product. 

The  rhizome  of  Panax  rep  ens,  growing  in  Japan,  contains  20.8 
per  cent,  of  a  non-toxic  saponin  with  hemolytic  properties. 

b.  UMBELLIFER^E  OR  CARROT  FAMILY.— The  plants 
are  herbs,  frequently  with  hollow  stems ;  alternate,  simple  or  com- 
pound leaves,  the  base  of  the  petiole  often  forming  an  inflated 
sheath ;  and  small  white,  yellowish,  greenish  or  somewhat  purplish 
flowers  occurring  in  simple  or  compound  umbels.     The  fruit  is  a 
cremocarp,  having  characters  which  are  of  important  taxonomic 


CLASSIFICATION  OF  ANGIOSPERMS.  637 

value,  as  the  presence  or  absence  of  secondary  ribs,  number  and 
position  of  the  vittse,  etc. 


FIG.  344.  Wild  Sarsaparilla  (Aralia  nudicaulis).  The  plant  produces  a  long,  cylin- 
drical rhizome  at  or  near  the  surface  of  the  ground,  and  sends  out  at  various  points  a  single, 
long-stalked  compound  leaf,  and  a  shorter,  naked  scape  bearing  2  to  7  umbels  of  greenish- 
'  white  flowers.  The  rhizome  is  sold  as  American  Sarsaparilla,  but  it  has  none  of  the  con- 
stituents of  the  true  Sarsaparilla. — After  Brown. 

Coriandruni  sativum  is  an  annual  herb  the  fruits  of  which  are 
official.  The  compound  leaves  are  bi-  or  tri-pinnate,  the  leaflets 


638 


A  TEXT-BOOK  OF  BOTANY. 


being  narrow  linear-lanceolate ;  and  the  flowers  are  white  or  rose- 
colored. 


FIG.  345.  Panax  quinquefolium  (Ginseng):  A,  upper  portion  of  plant  showing  pal- 
mately-compound  leaves  with  long-stalked  leaflets  and  the  berry-like  drupes;  B,  fusiform 
root;  C,  roots  showing  characteristic  stem  scars  at  the  upper  portion. — From  a  photograph 
by  Wyss.  (See  also  Fig.  166,  p.  305.) 

Conium  maculatum  or  Poison  Hemlock  is  a  tall,  erect,  branch- 
ing, biennial  plant,  with  purplish  spotted  stems,  .large  pinnately 


CLASSIFICATION  OF  ANGIOSPERMS.  639 

decompound  leaves  and  small,  white  flowers   (Figs.  346,  347). 
The  fruit  as  well  as  the  leaves  is  used  in  medicine. 

Carum  Carvi  (Caraway)  is  a  biennial  herb  with  bi-  or  tri- 
pinnate,  deeply  incised  leaves,  and  white  flowers.  The  fruit  is 
official  and  the  leaves  are  also  used  in  medicine. 

Pimpinella  Anisum  is  a  small,  hairy,  annual  herb.  The  leaves 
are  variable,  the  lower  being  somewhat  cordate  and  serrate,  the 
middle  distinctly  lobed,  and  the  upper  ones  trifid ;  the  flowers  are 
white.  The  fruit  is  official  and  is  also  used  for  flavoring. 

Fceniculum  vulgar e  is  an  annual  or  perennial,  glabrous  herb 
with  very  finely  dissected  leaves,  the  divisions  being  narrow-linear. 
The  flowers  are  yellow,  and  the  involucre  and  involucels  are 
wanting.  The  fruit  is  official. 

Ferula  fcctida  is  a  stout,  perennial  herb  with  few,  ternately 
compound  leaves  and  small,  polygamous,  light  yellow  flowers.  The 
root  is  rather  large  and  yields  the  gum-resin  asafetida.  Asafetida 
is  also  derived  from  other  species  of  Ferula. 

Ferula  Sumbul  is  a  tall  perennial  herb  with  purplish  latex- 
containing  stems.  The  basal  leaves  are  ternately  compound  and 
with  amplexicaul  base.  The  leaves  decrease  in  size  from  the  base 
upward,  becoming  bract-like  near  the  inflorescence.  The  flowers 
are  polygamous,  resembling  those  of  F.  fcetida.  The  root  is  official 
and  is  probably  also  obtained  from  other  closely,  related  species  of 
Ferula. 

A  large  number  of  the  plants  belonging  to  the  Umbelli ferae 
contain  essential  oils,  resins,  gum-resins  and  related  substances. 
The  gum-resin  AMMONIAC  is  an  exudation  found  on  the  stem  and 
branches  of  Dorema  Ammoniacum  and  other  species  of  Dorema 
as  a  result  of  the  sting  of  an  insect.  The  plant  is  found  in  Western 
Asia.  The  gum-resin  occurs  in  yellowish-brown,  globular,  or 
somewhat  flattened  tears  which  are  brittle,  milky-white  internally, 
with  a  distinct  balsamic  odor  and  bitter,  acrid,  nauseous  taste.  It 
contains  a  small  quantity  of  volatile  oil  having  the  odor  of  Angelica. 
AFRICAN  AMMONIAC  is  obtained  from  Ferula  tingitana  growing 
in  Northern  Africa  and  Western  Asia. 

The  gum- resin  GALBANUM  is  obtained  by  incising  the  root  of 
Ferula  galbaniflua  and  other  species  of  Ferula  growing  in  the 
Levant.  Galbanum  occurs  in  pale  yellowish-brown  agglutinated 


A  TEXT-BOOK  OF  BOTANY 


FlG.  346. — Poison  Hemlock  (Conium  maculatum),  showing  the  spreading  habit  of  the  plant 
and  the  prominent  large  compound  umbels  of  flowers. — After  Bornemann. 


CLASSIFICATION  OF  ANGIOSPERMS. 


641 


FIG.  347.  Conium  maculatum,  showing  the  large  decompound  leaves  with  pinnatifid 
leaflets,  and  the  compound  umbels  of  flowers,  with  detached,  enlarged  views  of  umbels  and 
a  compound-  umbel.— rFrom  Bulletin  No.  26,  U.  S.  Department  of  Agriculture. 

The  fresh  juice  of  Conium  maculalum  was  used  in  the  preparation  of  the  famous  hemlock 
potion  which  was  employed  by  the  Greeks  in  putting  their  criminals  to  death.  This  is  not 
the  same  plant  under  the  name  of  Conium  which  is  referred  to  in  Roman  and  mediaeval  Latin 
literature,  the  latter  being  Cicuta  virosa,  which  does  not  grow  in  Greece  and  in  Southern 
Europe. 


642 


A  TEXT-BOOK  OF  BOTANY. 


V;  St 


FIG.  348.  Cicuta  maculata  (Water  Hemlock):  A,  upper  part  of  stern  with  leaves  and 
compound  umbels;  B,  base  of  the  stem  and  the  thick  tuberous  roots;  C,  cross-section  of 
stem  showing  part  of  a  mestome-strand  and  the  pith  with  secretory  cells  (a),  vessels  (v), 
libriform  (St),  pith  (p);  D,  a  flower  showing  petals  with  long  inflexed  summit  and  the  five 
stamens  inserted  on  the  disk  that  crowns  the  ovary;  E,  the  fruit;  F,  fruit  in  longitudinal 
section  showing  the  two  ovules;  G,  cross-section  of  a  mericarp  showing  the  six  vittae  or  oil- 
tubes. — After  Holm. 

tears,  forming  a  more  or  less  hard  mass,  which  'is  brittle  when 
cold  but  soft  and  sticky  at  37°  C. ;  the  odor  is  distinct,  balsamic ; 
the  taste  bitter  and  acrid.  It  contains  from  10  to  20  per  cent,  of  a 
volatile  oil  composed  of  d-pinene,  cadinene,  and  other  principles. 


CLASSIFICATION  OF  ANGIOSPERMS.  643 

A  volatile  oil,  known  as  AJOWAN  OIL,  and  containing  thymol, 
is  obtained  from  the  fruit  of  Carum  Ajowan  of  Europe,  Asia  and 
Africa.  A  volatile  oil  containing  APIOL  is  found  in  the  fruit  and 
leaves  of  the  garden  parsley  (Petroselinum  sativum).  DILL  OIL 
is  obtained  from  the  garden  Dill  (Anethum  graveolens}.  The 
fruit  of  Sweet  cicely  ( Washingtonia  longistylis)  yields  a  volatile 
oil  known  as  sweet  anise  oil,  which  contains  anethol.  The  oil 
of  water  fennel  ((Enanthe  Phellandrium)  contains  about  80  per 
cent,  of  phellandrene.  CUMIN  OIL  is  obtained  from  Cuminum 
Cyminum  of  Turkestan  and  Egypt,  and  contains  cymene. 

The  roots  of  a  number  of  the  plants  of  this  family  contain 
volatile  oils,  as  Lovage  (Levisticum  officinale)  of  Southern 
Europe;  European  angelica  or  garden  angelica  (Angelica  Arch- 
angelica)  ;  American  angelica  or  the  purple-stemmed  angelica 
(A.  atropurpurea)  found  in  the  Northern  and  Eastern  United 
States  and  Canada;  Wild  angelica  (A.  sylvestris)  of  Europe. 

r.  CORNACEyE  OR  DOGWOOD  FAMILY.— The  plants 
are  shrubs  or  trees  with  simple,  opposite  leaves,  and  flowers  in 
cymes  or  heads,  which  in  the  case  of  the  Flowering  dogwood 
(Cornus  florida)  are  subtended  by  four  large,  petal-like,  white,  or 
pinkish  bracts.  The  fruit  is  a  I-  or  2-seeded  drupe. 

The  bark  of  Cornus  florida,  a  shrub  or  small  tree  growing  in 
the  United  States,  contains  a  bitter  principle,  cornin ;  and  a  small 
quantity  of  gallic  and  tannic  acids. 

Aucuba  japonica,  a  plant  indigenous  to  the  Himalayas,  China 
and  Japan  and  extensively  cultivated  on  account  of  its  crimson 
berries,  contains  a  glucoside  aucubin.  It  is  found  in  the  different 
varieties  and  varies  in  amount  from  0.31  to  1.96  per  cent. 

METACHLAMYDE^E  OR  SYMPETAL.E. 

This  is  the  highest  group  of  plants  and  is  marked  by  the  follow- 
ing characters :  The  corolla  is  sympetalous ;  the  flowers  are  mostly 
perigynous  or  epigynous  and  both  the  corolla  and  stamens  are 
borne  on  the  perianth  tube.  The  number  of  parts  is  definite,  there 
being  5  sepals,  5  petals,  5  or  10  stamens  and  2  or  5  carpels.  This 
sub-class  includes  but  six  orders,  to  which,  however,  belong  a  large 
number  of  medicinal  and  economic  plants. 


644  A  TEXT-BOOK  OF  BOTANY. 

I.    ORDER   ERICALES. 

The  plants  of  this  order  are  distinguished  by  the  fact  that  the 
stamens  are  mostly  free  from  the  perianth  tube. 

a.  PIROLACE^E. — The  plants  are  small,  mostly  evergreen 
perennials,  and  are  represented  in  the  United  States  by  several 
genera. 

Chimaphila  umbellata  (Prince's  pine  or  Pipsissewa)  is  a  small 
trailing  or  creeping  plant  producing  distinct  flower-  and  leaf- 
branches.  The 'leaves  are  used  in  medicine.  The  flowers  are  in 
small  corymbs  and  the  petals  are  white  or  pinkish.  In  Chimaphila 
maculata  the  leaves  are  lanceolate,  mottled  with  white  along  the 
veins  and  the  flowers  are  considerably  larger. 

With  the  Pirolaceae  are  sometimes  grouped  the  saprophytic 
plants  of  the  genus  Monotropa.  There  are  two  representatives  of 
this  genus  which  are  common  in  the  United  States,  namely,  Indian 
pipe  (Monotropa  uniflora)  and  false  beech-drops  (M.  Hyp opitys). 
The  latter  contains  a  glucoside  or  an  ester  of  methyl  salicylate,  and 
a  ferment  gaultherase  (Fig.  349). 

b.  ERICACEAE  OR  HEATH   FAMILY.— This  is  a  large 
family  and  the  plants  are  widely  distributed,  especially  in  the 
northern  mountainous  parts  of  both  the  Eastern  and  Western  Con- 
tinents.    They  vary  from  perennial  herbs  to  trees.     The  flowers 
are  usually  regular,  the  stamens  being  mostly  2-spurred    (Fig. 
221,  S),  and  the  fruit  is  either  a  superior  or  inferior  drupe  or 
berry  (Fig.  280,  H). 

Arctostaphylos  Uva-Ursi  is  a  low  branching  shrub  which  trails 
or  spreads  on  the  ground.  The  leaves  are  used  in  medicine  (Fig. 
355).  The  flowers  are  small,  white  or  pink,  few  and  in  short 
racemes.  The  fruit  is  a  red,  globular  drupe. 

Trailing  arbutus  (Epigcca  re  pens)  is  a  trailing,  shrubby,  hairy 
plant  with  broadly  elliptical  or  ovate,  coriaceous,  evergreen  leaves 
and  white  or  rose-colored,  fragrant  flowers  which  are  either  per- 
fect, with  styles  and  filaments  of  varying  length,  or  dioecious.  The 
leaves  contain  similar  constituents  to  those  in  Uva-Ursi  and 
Chimaphila  (Fig.  353). 

The  leaves  of  wintergreen  (Gaultheria  procumbens)  are  the 
source  of  true  oil  of  wintergreen,  which  consists  almost  entirely 


CLASSIFICATION  OF  ANGIOSPERMS. 


645 


FIG.  349.  Indian  Pipe  (Monotropa  uniflora),  a  parasitic  plant  of  the  Ericaceae  growing 
on  roots  of  various  plants  and  on  decomposing  vegetable  matter.  The  stems  are  white,  or 
yellowish-red,  furnished  with  scales  or  bracts  in  place  of  leaves,  and  surmounted  usually' 
with  a  single  nodding  flower  becoming  in  fruit  erect. — After  Troth. 


646 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  350.  Purple  Azalea  or  Pinkster  Flower  (Rhododendron  nudiflorum),  showing  the 
upright  lower  stalk  surmounted  by  several  spreading  branches,  each  bearing  a  number 
of  showy  tubular  flowers  at  its  extremity.  The  flowers  of  this  plant  often  appear  before 
the  leaves. 


CLASSIFICATION  OF  ANGIOSPERMS. 


647 


of  methyl  salicylate.     It  contains  a  small  quantity  of  an  alcohol 
and  an  ester  giving  the  characteristic  odor.     The  same  principles 


FIG.  351.  Great  Laurel  or  Rose  Bay  (Rhododendron  maximum),  an  evergreen  shrub 
found  in  low  woods  and  along  streams,  chiefly  in  the  mountains  of  the  eastern  United  States, 
often  forming  impenetrable  thickets.  It  is  one  of  the  most  beautiful  of  the  flowering  shrubs, 
producing  from  scaly,  cone-like  buds  numerous  corymbose  clusters  of  flowers  varying  from 
pale  rose  to  white. — After  Troth. 

probably  also  occur  in  several  other  species  of  Gaultheria  (Fig. 
354). 


648 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  352.  Mountain  Laurel  (Kalmia  latifolia).  This  is  a  handsome  evergreen  shrub 
growing  on  rocky  hills  and  in  damp  soils  in  the  eastern  United  States.  The  foliage  is  bright 
green,  and  the  showy  flowers  occur  in  terminal  corymbs,  being  either  of  a  whitish  or  pink 
•  color.  The  leaves  of  many  species  of  Kalmia  are  said  to  be  poisonous  to  animals,  which  is 
especially  true  of  the  Sheep  Laurel,  known  as  Lambkill  (Kalmia  anguslifolia),  which  is 
not  infrequent  on  hillsides  and  pastures. — After  Troth. 

The  poisonous  principle  andromedotoxin  is  found  in  a  number 
of  species  of  Rhododendron,  Leucothoe,  and  Pieris.  This  principle 
is  a  powerful  emetic  and  one  of  the  most  toxic  principles  known. 


CLASSIFICATION  OF  ANGIOSPERMS.  649 


FIG.  353.  Trailing  Arbutus  or  Mayflower  (Epigcea  repens).  This  is  one  of  the  first 
of  the  early  spring  flowering  plants.  It  is  a  prostrate  woody  plant,  usually  more  or  less 
covered  up  with  the  autumn  leaves  and  with  rounded  and  heart-shaped  evergreen  leaves. 
The  flowers  occur  in  small  axillary  clusters,  are  of  a  rose-red  color,  dimorphic  as  to  styles 
and  stamens,  and  are  very  fragrant.  They  are  transplanted  with  difficulty,  and  require 
an  acid  soil,  as  do  many  other  Ericaceae. — After  Troth. 


650 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  354.  Wintergreen,  teaberry  (Gaultheria  procumbens),  a  low  shrub  producing  slender 
stems  lying  at  or  beneath  the  surface  of  the  earth  and  having  ascending  flowering  branches 
rising  to  a  height  of  7  to  12  cm.  The  leaves  are  evergreen,  obovate  or  oval,  and  very  spar- 
ingly toothed;  the  flowers  are  whitish,  urn-shaped  and  axillary.  The  fruit  is  capsular,  sur- 
rounded by  the  fleshy  calyx,  which  forms  the  reddish  aromatic  globular  berries. — Bureau 
of  Plant  Industry,  U.  S.  Department  of  Agriculture. 


CLASSIFICATION  OF  ANGIOSPERMS.  651 


FIG.  355.  Bearberry  (Arctostaphylos  Uva-ursi),  a  trailing,  shrubby  plant  with  thick 
evergreen,  alternate  leaves  and  whitish  flowers  in  terminal  racemes.  The  fruit  is  a  globular, 
reddish,  berry -like  drupe  about  the  size  of  a  pea,  with  a  mealy,  insipid  pulp.  A .  alpina,  grow- 
ing in  the  Alpine  summits  of  Maine  and  New  Hampshire,  develops  a  blackish  drupe  with  a 
juicy  and  edible  pulp. — Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture. 


652 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  356.  Black  or  High-bush  Huckleberry  (Gaylussacia  baccala  or  G.  resinosa).  An 
erect  shrub  with  straggling  branches,  having  leaves  and  flowers  that  are  densely  covered 
with  resinous  dots;  the  leaves  vary  from  oval  to  oblong;  the  flowers  are  reddish-yellow, 
clustered  in  short  racemes  on  terminal  and  axillary  branches;  the  fruit  is  a  sweet,  blackish, 
berry-like  drupe.  In  some  varieties  it  is  smooth  and  shiny,  in  others  it  is  bluish  and  covered 
with  a  bloom. — After  Brown. 


CLASSIFICATION  OF  ANGIOSPERMS. 


653 


It  probably  occurs  in  the  nectar  of  the  flowers  of  Kalmia  and 
Rhododendron,  being  the  cause  of  the  poisonous  properties  of  the 
honey  from  this  source.  The  leaves  of  several  species  of  laurel 


FIG.  357-  Dwarf  Blueberry  or  Early  Sweet  Blueberry  (Vaccinium  pennsylvanicum') . 
A  low  shrub  growing  to  a  height  of  2  to  6  dm.  The  leaves  are  lanceolate  or  oblong,  of  a 
bright  green  color  and  minutely  serrate  with  bristle-pointed  teeth;  the  flowers  are  few,  in 
short  racemes,  the  corolla  being  whitish  and  cylindrical;  the  berries  are  bluish,  covered  with 
a  bloom,  and  ripen  during  July  and  August. — After  Brown. 

v( Kalmia)   contain  considerable  quantities  of  this  principle,  and 
are  poisonous  to  cattle. 

The  plants  of  the  genus  Gaylusaccia  are  small  shrubs  distin- 
guished by  having  an  inferior,  berry-like  drupe  with  ten  loculi. 
To  this  genus  belong  the  huckleberries,  as  black  huckleberry 


654 


A  TEXT-BOOK  OF  BOTANY. 


(G.  baccata)  ;  blue  huckleberry  (G.  frondosa)  ;  and  dwarf  huckle- 
berry (G.  dumosa).  The  latter  plant  grows  in  sandy  swamps 
in  both  the  United  States  and  Canada  and  the  fruit  ripens  in 
May  and  June.  The  fruits  of  the  other  two  species  ripen  in  July 
and  August  (Fig.  356). 


X« 


FIG.  358.  Low  Blueberry  or  Blue  Huckleberry  (Vaccinium  vacillqns').  A  small 
shrub  with  yellowish-green  branchlets  having  nearly  entire,  narrow,  obovate  leaves.  The 
flowers  are  in  racemose  clusters,  appearing  before  the  leaves  are  half  grown,  as  shown  in 
the  illustration;  the  corolla  is  pinkish-white,  oblong-cylindrical,  and  somewhat  constricted 
at  the  throat.  The  berries  are  blue,  covered  with  a  bloom,  and  ripen  in  August  and  Sep- 
tember.— After  Brown. 

The  plants  belonging  to  the  genus  Vaccinium  vary  from  very 
small  shrubs  to  tree-like  shrubs  and  the  fruit  is  an  inferior, 
5-locular  berry  with  numerous  seeds.  The  blueberries  or  bilberries 
(whortleberries)  are  the  fruits  of  several  species  of  Vaccinium. 


CLASSIFICATION  OF  ANGIOSPERMS. 


6SS 


The  low-bush  blueberry  (V .  pennsylvanicum)  yields  the  berries 
which  ripen  in  June  and  July,  while  the  high-bush  blueberry  ( V. 
corymbosum)  furnishes  the  fruits  which  are  found  in  the  market 
in  July  and  August  (Figs.  357,  358). 


FIG.  359.  Small  Cranberry  (Vaccinium  Oxycoccos).  A  trailing  evergreen  shrub,  which 
produces  slender  erect  or  ascending  branches  with  oblong  revolute  leaves,  rose-colored 
nodding  flowers,  and  a  4-locular,  reddish,  acid  fruit.  The  berry  of  the  American  Cranberry 
(V.  macrocarpon)  is  much  larger  and  furnishes  the  fruit  of  the  market.  There  are  many 
varieties  in  cultivation. — After  Brown. 

The  bilberry  of  Europe,  Vaccinium  Myrtillus,  a  plant  growing 
in  Northern  Europe  and  Asia  and  the  Western  United  States  and 
Canada,  is  said  to  destroy  Bacillus  typhosus  and  B.  Coli,  an 
infusion  of  the  dried  berries  being  used  for  this  purpose.  The 
leaves  of  this  plant  contain  ericolin  and  kinic  acid. 


656  A  TEXT-BOOK  OF  BOTANY. 

Cranberry  is  the  fruit  of  several  species  of  Vaccinium  which 
are  sometimes  grouped  in  a  separate  genus,  Oxycoccos.  There 
are  two  principal  species :  The  large  or  American  Cranberry  ( V . 
macrocarpon)  in  which  the  berries  are  ovoid  or  oblong  and  the 
small  or  European  Cranberry  ( V.  Oxycoccos)  in  which  the  berries 
are  globose.  The  berries  contain  from  1.4  to  2.8  per  cent,  of  citric 
acid;  and  a  bitter  glucoside,  oxycoccin  (Fig.  359). 

Many  attempts  have  been  made  to  cultivate  the  blueberry, 
trailing  arbutus,  and  other  plants  of  the  Ericaceae.  For  some 
years  a  number  of  the  agricultural  experiment  stations  in  the 
United  States  have  attempted  to  grow  the  blueberry  as  a  fruit, 
but  none  of  these  attempts  has  resulted  in  the  commercial  success 
of  blueberry  culture,  and  the  experimental  results  have  been  chiefly 
of  a  negative  character.  The  reason  for  this  has  been  due,  as 
pointed  out  by  Coville  (Bull.  No.  193,  Bureau  of  Plant  Industry, 
U.  S.  Department  of  Agriculture),  to  a  misunderstanding  of  the 
soil  requirements  for  this  plant.  Plants  will  thrive  only  in  soil 
having  the  following  properties  :  I.  The  soil  must  have  a  distinctly 
acid  reaction,  such  as  is  found  in  peat  bogs  or  on  the  surface  of 
the  ground  in  sandy,  oak,  or  pine  woods.  2.  Aeration  of  the  soil 
is  necessary.  The  rootlets  of  the  swamp  blueberry  are  remarkable 
in  having  no  root  hairs  whatsoever,  so  that  their  absorptive  surface 
is  only  about  one-tenth  that  of  other  plants  having  root  hairs. 
The  growth  of  the  rootlet  of  the  blueberry  is  much  less  than  that 
of  other  plants,  being  about  at  the  rate  of  only  I  mm.  per  day  under 
favorable  conditions.  The  rootlets  of  healthy  blueberry  plants  are 
inhabited  further  by  a  mycorrhizal  fungus  which  apparently  has 
the  property  of  assimilating  nitrogen. 

II.    ORDER   PRIMULALES. 

Of  the  three  families  belonging  to  this  order,  there  are  two 
which  are  to  some  extent  represented  in  temperate  regions. 

a.  PRIMULACE^:  OR  PRIMROSE  FAMILY.— The  plants 
are  mostly  perennial  herbs  with  perfect  regular  flowers,  and  capsu- 
lar  fruits.  The  family  is  chiefly  of  horticultural  interest,  as  it 
contains  the  genera  Primula  and  Cyclamen.  There  are  several 
species  of  Primula  cultivated,  and  they  are  among  the  most  popular 
and  beautiful  of  the  florist's  flowers  (Fig.  360).  Several  of  the 


CLASSIFICATION  OF  ANGIOSPERMS. 


657 


FIG.  360.  Primula  (Primula  obconica),  one  of  several  species  of  Primula  which  are 
cultivated  in  greenhouses  and  as  house  plants.  The  leaves  are  circular  heart-shaped, 
long  petiolate,  and  very  hairy;  the  flowers  are  pinkish  or  lilac  color  and  occur  in  umbels. 
The  hairs  of  this  plant  are  very  irritating,  and  cause  a  dermatitis  similar  to  that  produced 
by  poison  ivy. — After  Guernsey. 

species  are  found  in  Northern  United  States  and  Canada.    Dur- 
ing recent  years  it  has  been  reported  that  the  wild  primrose  (P. 
farinosa)  and  also  the  cultivated  species  (P.  obconica)  possess 
42 


658  A  TEXT-BOOK  OF  BOTANY. 

hairs  which  are  very  irritating  and  cause  a  dermatitis  similar  to  that 
produced  by  poison  ivy. 

A  number  of  the  primulas  have  been  examined  chemically. 
The  subterranean  parts  of  Primula  officinalis  contain  two  crystal- 
line glucosides,  primeverin  and  primulaverin,  which  by  the  action 
of  the  ferment,  primeverase,  produce  an  anise-like  odor.  The 
odors  of  the  other  species  of  Primula  are  probably  due  to  distinct 
glucosides:  (a)  one  producing  an  anise-like  odor,  as  in  P.  ofUci- 
nalis,  P.  capitata,  and  P.  denticulata;  (b)  one  producing  the  odor 
of  methyl  salicylate,  as  in  P.  longiflora,  P.  elatior,  and  P.  vulgaris ; 
(c)  one  producing  the  odor  of  coriander,  as  in  P.  auricula,  P. 
panonica,  and  P.  Palinuri.  The  flowers  of  a  number  of  species 
are  light  in  color  and  somewhat  luminous  in  the  dark. 

b.  PLUMBAGINACE^E  OR  LEADWORT  FAMILY.— 
Perennial,  mostly  acaulescent  herbs,  growing  in  saline  locations. 
Sea  lavender  or  marsh  rosemary  (Limonium  carolinianum)  is 
found  in  the  salt  meadows  from  Labrador  to  Texas.  The  plant 
is  reported  to  contain  tannin  and  has  been  used  in  medicine. 

III.    ORDER  EBENALES. 

This  order  includes  three  families  which  are  chiefly  indig- 
enous to  the  Tropics.  The  leaves  are  alternate,  and  the  flowers 
vary  in  the  different  families,  the  fruit  being  a  berry  or  drupe. 

a.  SAPOTACE^:  OR  SAPODILLA  FAMILY.— The  plants 
usually  have  a  milky  latex,  and  many  of  them  yield  GUTTA-PERCHA, 
of  which  the  following  may  be  mentioned:  Palaquium  Gutta,  P. 
oblongifolium,  P.  borneense  and  P.  Treubii,  all  growing  in  the 
East  Indies.  The  latex  is  obtained  by  incising  the  trees  and  collect- 
ing the  exuding  juice  in  suitable  vessels.  It  soon  coagulates  and 
forms  grayish  or  reddish-yellow  hard  masses,  which  are  plastic 
at  65°  to  70°  C.  Owing  to  the  fact  that  the  material  is  plastic 
when  heated  and  firm  and  tenacious  when  cold,  it  is  used  for  a 
variety  of  purposes,  as  in  the  manufacture  of  surgical  instruments 
and  as  a  material  for  filling  teeth.  Gutta-percha  as  it  exudes  from 
the  tree  is  supposed  to  consist  of  a  terpene-like  hydrocarbon, 
which  on  coagulation  is  oxidized,  forming  a  number  of  resinous 
compounds.  The  plants  of  other  genera  of  this  family  also  yield 


CLASSIFICATION  OF  ANGIOSPERMS.  659 

gutta-percha,  as  Mimusops  Balata,  M.  Elengi,  and  about  fifteen 
species  of  Payena  growing  in  the  East  Indies. 

GUM  BALATA  is  obtained  from  Mimusops  Balata,  a  tree  of 
Guiana.  The  gum  is  more  resinous  and  flexible  than  gutta-percha. 
It  contains  /?-amyrin  acetate  and  probably  lupeol  acetate. 

A  gum  resembling  gutta-percha  is  obtained  from  the  Sabodilla 
tree  (Achras  Sapota}.  This  gum  is  known  in  commerce  as  GUM 
CHICLE  and  is  obtained  from  Yucatan.  It  is  whitish,  brittle,  and 
yet  somewhat  elastic,  aromatic,  and  contains  45  per  cent,  of  a 
colorless  crystallizable  resin,  soluble  in  alcohol  and  ether;  and  18 
per  cent,  of  caoutchouc.  It  is  used  in  large  quantities  in  the  making 
of  chewing  gum. 

The  seeds  of  Illipe  butyracea  yield  a  fixed  oil  which  is  known 
as  VEGETABLE  BUTTER.  A  fixed  oil  is  also  obtained  from  other 
species  of  Illipe  as  well  as  various  species  of  Bassia,  Argania,  and 
Butyrospermum,  that  from  the  latter  being  known  as  "  shea 
butter." 

The  family  is  notable  on  account  of  the  hard  woods,  known  as 
IRONWOODS,  which  it  furnishes,  these  being  yielded  by  Mimusops 
Kauki  of  Farther  India  and  tropical  Australia  and  Argania  Side- 
roxylon  of  Southwestern  Morocco. 

A  number  of  species  also  yield  highly  prized  edible  fruits,  as 
the  SAPOTILLA  yielded  by  Achras  Sapota  indigenous  to  the  Antil- 
les and  cultivated  in  tropical  countries,  and  STAR  APPLE  yielded  by 
Chrysophyllum  Cainito  of  tropical  America. 

b.  EBENACE^:  OR  EBONY  FAMILY.— The  plants  differ 
from  those  of  the  preceding  family  in  not  containing  a  latex.  The 
flowers  are  monoecious  or  dioecious  and  they  usually  have  from  two 
to  eight  styles.  The  chief  interest  is  in  the  genus  Diospyros,  which 
yields  the  wood  known  as  EBONY.  Black  ebony  is  obtained  from 
various  species  of  Diospyros  growing  in  tropical  Africa,  and  Asia, 
and  the  Philippine  Islands.  White  ebony  is  obtained  from  several 
species  of  Diospyros  growing  in  the  Philippines.  A  red  ebony  is 
obtained  from  D.  rubra  of  Mauritius,  a  green  ebony  from  D. 
Chloroxyion  of  Farther  India,  and  a  striped  ebony  from  several 
species  growing  in  the  Philippines. 

PERSIMMON  fruit  is  obtained  from  Diospyros  virginiana,  a 
tree  growing  from  Rhode  Island  south  to  Texas.  The  astrin- 


660  A  TEXT-BOOK  OF  BOTANY. 

gency  of  the  unripe  fruit  is  due  to  the  tannin  which  it  contains. 
When  it  is  ripe,  which  is  not  until  after  the  appearance  of  frost, 
it  is  palatable  and  contains  considerable  malic  acid  and  sugars. 
The  Japanese  persimmon  is  a  cultivated  variety  of  D.  Kaki  and 
produces  a  large  orange-colored  fruit  which  is  not  uncommon  in 
the  fruit  markets  in  many  parts  of  the  world.  At  the  present 
time  the  plant  is  cultivated  in  California. 

The  bark  of  our  native  persimmon  is  used  in  medicine.  It 
contains  considerable  tannin  which  resembles  gallotannic  acid,  and 
a  crystalline  resinous  principle  with  a  peculiar  odor  and  slightly 
astringent  taste. 

c.  STYRACACE^  OR  STORAX  FAMILY.— The  flowers 
of  this  family  somewhat  resemble  those  of  the  Ebenacese,  but  the 
filaments  of  the  stamens  are  united  in  a  single  series,  and  there 
is  a  single  slender  style. 

Styrax  Benzoin  is  a  medium-sized  tree  with  long,  ovate,  acu- 
minate leaves  which  are  very  hairy  on  the  under  surface.  The 
flowers  occur  in  terminal  racemes,  and  are  silvery  white  on  the 
outer  surface  and  reddish-brown  on  the  inner  surface.  The  bal- 
samic resin  yielded  by  this  plant  is  official  as  benzoin. 

IV.    ORDER   GENTIANALES  OR   CONTORTS. 

The  plants  of  this  order  have  opposite  leaves,  the  flowers  are 
regular  and  the  gynaecium  consists  of  two  separate  carpels.  The 
order  includes  five  families,  all  of  which  furnish  medicinal  plants. 

a.  OLEACE^  OR  OLIVE  FAMILY.— This  family  is 
chiefly  of  interest  because  of  the  olive  and  manna  trees. 

The  olive  tree  (Olea  europcea)  is  indigenous  to  the  Orient  and 
is  now  cultivated  extensively  in  Southern  Europe,  Northern 
Africa,  the  islands  of  the  Mediterranean,  tropical  America,  includ- 
ing the  Southern  United  States,  and  in  California.  The  leaves 
are  narrow-lanceolate,  entire,  coriaceous  and  evergreen.  The 
flowers  are  small,  white,  diandrous  and  in  axillary  racemes.  The 
fruit  is  a  drupe,  the  sarcocarp  of  which  is  rich  in  a  fixed  oil 
known  as  olive  oil.  The  oil  is  obtained  by  expression,  and  is 
official.  Depending  upon  the  character  of  the  fruits  and  the 
amount  of  oil  which  they  yield,  over  forty  varieties  are  recognized. 


CLASSIFICATION  OF  ANGIOSPERMS.  661 

The  fresh  green  olives  contain  a  glucoside  oleuropein,  which 
disappears  on  the  maturation  of  the  fruit. 

Fraxinus  Ornus  is  a  tree  resembling  the  ash,  with  /-foliate 
leaves,  and  polygamous  flowers  occurring  in  compound  racemes. 
The  fruit  is  a  flat  samara  with  the  wing  at  the  apex.  The  sac- 
charine exudation  from  this  plant  is  official  as  manna. 

The  white  ash  (Fraxinus  americana)  is  a  valuable  tree  on 
account  of  the  timber  which  it  yields.  The  bark  contains  a  bitter 
glucoside,  f  raxin,  the  solutions  of  which  .are  fluorescent ;  a  bitter 
substance,  f  raxetin ;  an  ethereal  oil  of  a  butter-like  consistency, 
and  tannin.  Some  of  these  principles  are  also  found  in  other 
species  of  Fraxinus  growing  in  the  United' States  and  Europe. 

The  bark  of  the  fringe  tree  (Chionanthus  virginica)  of  the 
Southern  United  States  contains  an  intensely  bitter  glucosidal 
principle,  chionanthin,  and  possibly  also  saponin. 

The  leaves  of  the  garden  lilac  (Syringa  vulgaris)  contain  a 
crystalline  glucoside,  syringin,  and  syringopicrin,  both  of  which 
are  probably  also  found  in  other  species  of  Syringa  as  well  as 
the  bark  and  leaves  of  privet  (Ligustrum  vulgar e),  which  latter 
plant  is  extensively  used  for  hedges. 

b.  LOGANIACE^E  OR  LOGANIA  FAMILY.— The  plants 
are  variable  in  character,  being  herbs,  shrubs,  trees  or  vines. 

Yellow  jessamine  (Gelsemium  senipervirens)  is  a  twining 
woody  vine,  sometimes  trailing  on  the  ground  for  a  considerable 
distance.  The  leaves  are  oblong-lanceolate  and  evergreen.  The 
flowers  are  bright  yellow  and  dimorphic.  The  fruit  is  a  septi- 
cidally  dehiscent  capsule.  The  rhizome  .and  roots  are  official. 

Carolina  pink  (Spigelia  marilandica)  is  a  perennial  herb  with 
ovate-lanceolate,  more  or  less  acute  and  nearly  sessile  leaves. 
The  flowers  are  yellow  on  the  inner  and  scarlet  on  the  outer 
surface,  and  occur  in  a  I -sided  spike  or  scorpioid  cyme.  The  fruit 
is  a  loculicidal,  few-seeded,  2-valved  capsule  (Fig.  361).  The 
rhizome  and  roots  are  official. 

Strychnos  Nux-vomica  is  a  small  tree  with  broadly  elliptical, 
3-  to  5-nerved,  reticulately-veined,  somewhat  acuminate,  cori- 
aceous leaves.  The  flowers  are  whitish  and  in  terminal  cymes. 
The  fruit  is  a  berry  of  varying  size  and  contains  several  seeds, 
the  seeds  being  official.  ;i  ,1:.-:, 


662 


A  TEXT-BOOK  OF  BOTANY. 


CURARE,  which  is  used  by  the  Indians  of  South  America  as 
an  arrow-poison,  is  supposed  to  be  made  from  the  bark  of  Strych- 
nos  toxtfera,  growing  in  Guiana,  and  probably  other  species  of 


FIG.  361.      Carolina   pink    (Spigelia  marilandica)   showing  the  rhizome  bearing  two 
branches  with  opposite  leaves  and  flowers  in  terminal  scorpioid  cymes. 

this  genus.  The  active  principle  of  this  poison  is  the  alkaloid 
curarine,  which  when  administered  hypodermically  has  a  powerful 
action  resembling  that  of  digitalis. 


CLASSIFICATION  OF  ANGIOSPERMS. 


663 


FIG.  362.'  Closed  Gentian  (Gentiana  Andrewsii),  probably  one  of  the  most  abundant 
of  the  fall-flowering  Gentians.  It  is  a  perennial,  forming  stout,  leafy  stems,  terminated  by 
sessile  clusters  of  blue  flowers.  The  corolla  is  closed,  and  hence  this  Gentian  is  sometimes 
called  "Bottle  Gentian."  It  grows  in  moist  ground  throughout  most  of  the  eastern  United 
States  and  Canada. — After  a  photograph  by  Troth. 

c.  GENTIANACEyE  OR  GENTIAN  FAMILY.— The  plants 
are  mostly  herbs  with  regular,  perfect,  showy  flowers  occurring 
usually  in  small  cymes  or  racemes  (Fig.  362). 

Yellow  gentian   (Gentiana  lutea)    is  a  large,  perennial  herb 


664  A  TEXT-BOOK  OF  BOTANY. 

(see  Vol.  II)  with  large,  5-  to  7-nerved,  broadly  elliptical  leaves. 
The  flowers  are  yellow  and  occur  in  axillary  cymes.  The  fruit  is 
a  2-valved,  ovoid  capsule.  The  rhizome  and  roots  are  official. 
Many  of  the  gentians  are  among  the  most  highly  prized  of  the 
wild  flowers,  some  of  them,  as  the  fringed  gentian  (Gentiana 
crinita),  being  one  of  the  most  beautiful.  The  closed  gentian  (Fig. 
357)  >  s°  called  because  the  flowers  remain  closed,  is  quite  abundant 
in  moist  grounds  throughout  most  of  the  United  States  and 
Canada.  The  roots  of  a  number  of  species  of  American  gentian 
have  medicinal  properties  resembling  that  of  G.  lutea. 

Menyanthes,  the  yellowish-white  horizontal  rhizome  of  Men- 
yanthes  trifoliata  (Fig.  363),  contains  an  amorphous  glucoside 
which  is  slightly  soluble  in  water,  soluble  in  alcohol,  and  is  precipi- 
tated with  ta:nnm.  Upon  hydrolysis  menyanthin  yields  a  volatile 
oil  possessing  an  odor  reminding  one  of  bitter  almonds. 

SwertiaChirata. — The: entire  plant  is  official. 

HERBA  QENTAURII  MINORIS,  the  entire  plant  of  Erythrcca  Cen- 
taurium  of  Europe,  contains  a  glucoside,  erytaurin,  which  forms 
small  colorless  prismatic  and  bitter  crystals  and  is  slowly  hydro- 
lyzed  by  emulsin.  ' S abb atia  Elliot tii,  occurring  in  the  pine  barrens 
of  the  Southern  States;\is  known  as  the  "  quinine  herb." 

d.  APOCYNACE/E  Oil  DOGBANE  FAMILY.— The  plants 
vary  from  perennial  herbs  to  shrubs  and  trees,  contain  an  acrid 
latex,  and  have  flowers  with  the  stigmas  and  styles  united  and  the 
stamens  distinct.  They  are  mostly  found  in  the  Tropics. 

Apocynum  cannabinum  is  a  perennial  herb  with  erect  or  ascend- 
ing branches.  The  leayes  are  oblong-lanceolate,  opposite,  nearly 
sessile  or  with  short  petioles  (Figs.  226,  251).  The  flowers  are 
greenish-white,  the  lobes  of  the  corolla  being  nearly  erect  and 
the  tube  about  as  long  as  the  calyx.  The  fruit  is  a  slender,  terete 
follicle  containing  numerous  seeds  tipped  at  the  micropylar  end 
with  a  tuft  of  hairs.  The  root  is  official. 

The  root  of  a  closely  related  species,  namely,  spreading  dog- 
bane (Apocynum  andros&mifolium),  is  sometimes  substituted 
for  the  official  drug.  The  plant  is  distinguished  by  being  more 
spreading  in  its  habit.  The  leaves  are  ovate  (Figs.  226,  364),  the 
flowers  are  pinkish,  the  lobes  being  revolute,  and  the  tube  several 
times  as  long  as  the  calyx. 


CLASSIFICATION  OF  ANGIOSPERMS.  665 


FIG.  363.  Buckbean  or  Bogbean  (Menyanthes  trifoliata),  a  perennial  herb  with  a 
fleshy  horizontal  rhizome,  producing  erect  stems,  bearing  three  oval  or  oblong  leaflets, 
and  a  raceme  with  numerous,  white  or  rose-colored,  fringed  flowers.  The  plant  grows  in 
bogs  and  shallow  water  in  northern  United  States  and  Canada. — Bureau  of  Plant  Industry, 
U.  S.  Department  of  Agriculture. 


666 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  364.  Spreading  Dogbane  (Apocynum  androsamifolium) ,  a  perennial,  branching 
herb,  with  ovate-oblong,  opposite  leaves,  and  small,  pinkish  fragrant  flowers  occurring  in 
terminal  cymes.  All  parts  of  the  plants  contain  a  white  acrid  latex. — After  Brown. 

Strophanthus  Kombe. — The  plant  is  a  woody  climber  with 
elliptical-acuminate,  hairy  leaves.  The  flowers  are  few,  charac- 
terized by  long  styles,  and  occur  in  axillary  racemes.  The  fruit 
consists  of  two  long  follicles  containing  numerous  awned  seeds, 


CLASSIFICATION  OF  ANGIOSPERMS. 


667 


which  are  official.     In  the  closely  related  plant  S.  hispidus  the 
flowers  are  numerous  and  occur  in  terminal  cymes. 


FIG.  365.     Butterfly-weed  or  Pleurisy-root  (Asclepias  tuberosa),  showing  the  sessile,  oblong- 
ovate  leaves  and  the  simple,  many-flowered  umbels. 

QUEBRACHO  or  ASPIDOSPERMA  is  the  bark  of  Aspidosperma 
Quebracho-bianco,  a  tree  growing  in  Argentine.  It  contains  a 
number  of  alkaloids  and  is  used  to  some  extent  in  medicine. 


668  A  TEXT-BOOK  OF  BOTANY. 

The  leaves  and  bark  of  the  cultivated  oleander  (Nerium  Olean- 
der) contain  the  glucoside  oleandrin,  resembling  digitalin  in  its 
action ;  a  fluorescent  principle,  and  probably  several  other 
principles. 

The  common  periwinkle  (Vinca  minor)  contains  the  principle 
vincin,  which  is  supposed  to  be  a  glucoside  and  which  probably 
occurs  in  other  species  of  Vinca. 

e.  ASCLEPIADACE^:  OR  MILKWEED  FAMILY.— The 
plants  somewhat  resemble  those  of  the  Apocynaceae.  The  flower, 
however,  is  distinguished  by  having  distinct  styles,  a  5-lobed 
corona  connecting  the  corolla  and  stamens,  which  latter  are  mostly 
monadelphous,  and  pollen  grains  that  are  coherent,  forming  char- 
acteristic pairs  of  pollinia.  Few  of  the  plants  are  of  any  economic 
importance.  The  latex  of  the  stems  and  the  hairs  of  the  seeds  are 
deserving  of  attention.  PLEURISY  ROOT,  which  was  formerly  offi- 
cial, is  obtained  from  Asclepias  tuberosa,  a  plant  growing  in  the 
Eastern  United  States  and  one  of  the  two  members  of  this  genus 
that  have  orange-colored  flowers  (Fig.  365). 

CONDURANGO  is  the  bark  of  Marsdenia  Cundurango,  a  liane  of 
Ecuador  and  Colombia.  It  occurs  in  quilled  pieces,  the  bark 
being  from  2  to  6  mm.  thick.  Externally  it  is  brownish-gray 
and  with  a  more  or  less  scaly  cork.  The  taste  is  bitter,  acrid,  and 
aromatic.  The  drug  contains  an  amorphous  glucoside ;  an  unsatu- 
rated  alcohol  occurring  in  large  prisms;  and  a  volatile  oil  (0.3 
per  cent.). 

V.    ORDER  POLEMONIALES  OR  TUBIFLOR^. 

This  is  a  large  order  of  plants,  which  are  mostly  herbaceous. 
The  leaves  are  either  opposite  or  alternate ;  the  flowers  are  regular 
or  irregular,  the  stamens  being  usually  adnate  to  the  corolla. 

a.  CONVOLVULACE^:  OR  MORNING-GLORY  FAM- 
ILY.— The  plants  are  mostly  herbs  or  shrubs,  frequently  twining 
(to  the  left).  They  are  found  mostly  in  the  Tropics,  but  quite  a 
number  of  genera  occur  in  temperate  regions  (Fig.  366). 

Exogonium  Purga  is  a  perennial  twining  herb  with  distinctly 
veined,  cordate  leaves ;  purple  flowers  with  the  stamens  exserted, 
and  occurring  in  cymes.  The  fruit  is  a  2-locular  capsule.  The 


CLASSIFICATION  OF  ANGIOSPERMS. 


669 


plants  produce  slender  rhizomes  with  tuber-like  roots,  these  being 
used  in  medicine. 

Convolvulus  Scammonia  is  a  perennial  twining  herb,  with  a 
large  tap  root,  containing  a  resinous  latex,  and  is  the  source  of 
the  official  scammony  root.  The  leaves  are  sagittate ;  the  flowers 
are  large,  yellowish- white  and  funnel- form,  as  in  the  morning- 


FIG.  366.  Great  bind  weed  (Convolvulus  sepium)  showing  trailing  or  twining  habit, 
the  hastate  leaves  and  funnel-shaped  corolla.  The  plant  is  very  resistant  to  noxious  fumes 
and  is  usually  found  in  smelter  regions. 

glory,  and  occur  in  the  axils  of  the  leaves,  either  solitary  or  in 
clusters.    The  fruit  is  a  4-seeded,  4-locular,  dehiscent  capsule. 

A  number  of  the  plants  of  the  Convolvulaceae  are  cultivated, 
probably  the  most  important  of  which  is  the  SWEET  POTATO  vine 
(Ipomoca  Batatas},  a  plant  extensively  cultivated  in  tropical  and 
sub-tropical  countries  on  account  of  the  edible  tuberous  roots. 
The  roots  contain  from  3  to  10  per  cent,  of  sugar  and  9  to  15  per 
cent,  of  starch,  which  occurs  in  larger  proportion  in  plants  grown 


670  A  TEXT-BOOK  OF  BOTANY. 

in  sub-tropical  countries.  The  starch  is  a  commercial  product 
and  is  known  as  sweet-potato  starch  o-r  BRAZILIAN  ARROW-ROOT. 
The  grains  are  more  or  less  bell-shaped  and  2-  or  3-compound, 
about  the  size  of  wheat-starch  grains,  and  in  other  ways  resemble 
those  of  tapioca. 

To  this  family  also  belongs  rather  an  interesting  group  of 
parasitic  plants,  namely,  dodder  (Cuscuta).  They  contain  the 
principle  cuscutin,  and  quite  a  number  have  been  used  in  medicine. 

b.  POLEMONIACE^:  OR  POLEMONIUM  FAMILY.— 
A  family  mostly  of  herbs  and  chiefly  of  horticultural  interest.    It 
contains  the  genus  Phlox,  which  is  indigenous  exclusively  to  North 
America.    A  number  of  the  species  are  cultivated  and  are  included 
among  the  most   valuable   hardy,   herbaceous   perennials.     The 
flowers  are  among  the  most  beautiful  and  persistent  of  our  garden 
plants.     Another  interesting  genus  belonging  to  this   family  is 
Polemonium,  a  number  of  species  of  which  have  been  long  under 
cultivation  as  border  plants.    Polemonium  reptans  is  rather  com- 
mon in  the  woods  of  the  Northern  United  States  (Fig.  367). 

c.  HYDROPHYLLACE^E  OR  WATERLEAF  FAMILY.— 
The  plants  are  herbs  or  shrubs  which  are  indigenous  to  Western 
North  America.     Very  few  of  the  plants  of  this  family  are  of 
use  medicinally,  although  quite  a  number  are  ornamental  plants. 

Eriodictyon  calif ornicum  (E.  glutinosum)  or  Yerba  Santa 
is  a  shrub  growing  in  Northern  Mexico  and  California.  The 
leaves  are  official  (Fig.  368).  The  flowers  are  funnel-form,  white 
or  purple,  occurring  in  cymes.  The  fruit  is  a  dehiscent  capsule 
and  the  seeds  are  small  and  few. 

d.  BORAGINACE^      OR      BORAGE      FAMILY.— The 
plants  are  mostly  herbs  with  regular  blue  flowers,  occurring  in 
scorpioid   inflorescence.     The  best   examples   of   the  group   are 
the  forget-me-not    (Myosotis),  the   roots  of   several   species   of 
which  have  been  used  in  medicine ;  and  the  garden  heliotrope 
(Heliotropum  peruvianum) ,  the  fragrance  of  the  flowers  being 
due  to  a  volatile  oil.     This  plant,  as  well  as  other  species  of 
Heliotropum,  contains  a  poisonous  volatile  alkaloid. 

At  one  time  considerable  interest  attached  to  ALKANET,  the  root 
of  Alkanna  tinctoria  of  Southern  Europe  and  Asia,  on  account 
of  the  red  coloring  principle  alkannin,  which  is  soluble  in  alcohol, 


CLASSIFICATION  OF  ANGIOSPERMS.  671 


FlG.  367.     Greek  Valerian  (Polemonium  reptans),  a  perennial,  2  to  4  dm.  in  height,  having 
alternate  pinnate  leaves  and  light  blue  flowers  in  corymbs. — After  Brown. 

ether,  fixed  and  ethereal  oils,  but  insoluble  in  water.  COMFREY 
or  SYMPHYTUM  is  the  root  of  Symphytum  officinale  and  other 
species  of  this  genus  naturalized  from  Europe  in  waste  places  in 
the  United  States.  It  occurs  on  the  market  in  small,  purplish- 


672 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  368.  Yerba  Santa  (Eriodictyon  calif  or  m  cum) ,  a  low,  evergreen,  aromatic  shrub, 
the  leaves  and  stems  being  covered  with  a  resinous  exudation.  The  leaves  are  lanceolate, 
irregularly  serrate  or  nearly  entire,  and  woolly  hairy  beneath;  the  flowers  are  violet  or 
purple  in  color,  and  occur  in  cymose  panicles. — Bureau  of  Plant  Industry,  U.  S.  Depart- 
ment of  Agriculture. 


CLASSIFICATION  OF  ANGIOSPERMS.  673' 

black,  more  or  less  curved  pieces,  which  are  quite  mucilaginous 
and  astringent  to  the  taste.  The  drug  contains  a  gluco-alkaloid, 
consolidin,  and  an  alkaloid,  cynoglossine.  It  also  contains  a  small 
amount  of  amylo-dextrin,  i.e.,  starch  which  is  not  colored  blue  with 
iodine,  and  tannin.  The  root  and  herb  of  HOUND'S  TONGUE 
(Cynoglossum  officinale)  are  both  used  in  medicine.  The  drug 
contains  the  powerful  alkaloid  cynoglossine,  which  resembles  cura- 
rine  in  its  action ;  and  the  gluco-alkaloid,  consolidin. 

e.  VERBENACE^:  OR  VERVAIN  FAMILY.— The  plants 
are  chiefly  herbs  or  shrubs  with  usually  opposite  or  verticillate 
leaves  and  more  or  less  irregular  flowers  (Fig.  369). 

To*  this  family  belongs  the  group  of  verbenas,  some  of  which 
are  used  in  medicine,  as  blue  vervain  (Verbena,  hastata),  which 
resembles  eupatorium  in  its  medicinal  properties ;  nettle-leaved 
vervain  (V.  urticifolia) ,  which  contains  a  bitter  glucoside.  The 
drug  LIPPIA  MEXICANA  consists  of  the  leaves  of  Lippia  dulcis 
mexicana,  and  contains  a  volatile  oil,  the  camphor  lippiol,  tannin, 
and  quercetin.  Lippia  citriodora,  found  growing  in  the  central 
part  of  South  America,  contains  a  volatile  oil,  of  which  citral  is 
a  constituent.  TEAK-WOOD,  which  is  one  of  the  hardest  and  most 
valuable  of  woods,  is  derived  from  the  teak  tree  (Tectona 
gmndis),  a  large  tree  indigenous  to  Farther  India  and  the  East 
Indies. 

/.  LABIATE  OR  MINT  FAMILY.— The  plants  are  mostly 
aromatic  herbs  or  shrubs,  with  square  stems,  simple,  opposite 
leaves,  bilabiate  flowers,  and  a  fruit  consisting  of  four  nutlets. 
The  calyx  is  persistent,  regular  or  2-lipped  and  mostly  nerved. 
The  corolla  is  mostly  2-lipped,  the  upper  lip  being  2-lobed  or 
entire,  and  the  lower  mostly  3-lobed.  The  stamens  are  adnate 
to  the  corolla  tube,  and  are  either  4  and  didynamous,  or  2  per- 
fect and  2  aborted.  The  ovary  is  deeply  4-lobed  (Fig.  280,  /). 

The  Labiatse  are  especially  distinguished  on  account  of  the 
volatile  oils  which  they  yield,  and  a  few  contain  bitter  or  glucosidal 
principles. 

i.  The  following  PLANTS  ARE  USED  IN  MEDICINE: 

Scutellaria  lateriftora  (skullcap).  The  plant  is  a  perennial 
herb  producing  slender  stolons  somewhat  resembling  those  of 
43 


674 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  369.     Blue  Vervain  (Verbena  hastata),  a  tall,  perennial  herb,  with  oblong-lanceolate 
leaves,  and  numerous  terminal  spikes  of  violet-blue  flowers. — After  Brown. 


CLASSIFICATION  OF  ANGIOSPERMS. 


6/5 


FIG.  370.  Mad-dog  Skullcap  (Scutellaria  later i flora),  a  perennial  herb  growing  in 
wet,  shady  places  with  an  upright,  quadrangular  stem,  bearing  opposite  ovate-oblong, 
serrate  leaves,  in  the  axils  of  which  are  formed  the  blue  bilabiate  flowers. — Bureau  of  Plant 
Industry,  U.  S.  Department  of  Agriculture. 

peppermint  and  spearmint.     The  stems  are  erect  or  ascending, 
commonly  branching  and  from  22  to  55  cm.  high  (Fig.  370). 


676  A  TEXT-BOOK  OF  BOTANY. 

Marrubium  vulgar e  (white  hoarhound)  is  a  perennial  woolly 
herb  with  ascending  branches;  the  leaves  and  flowering  tops  are 
used  in  medicine. 

Salvia  officinalis  or  garden  sage  is  a  perennial,  somewhat 
shrubby,  pubescent  herb.  The  leaves  are  ovate,  crenulate.  The 
flowers  are  bluish,  somewhat  variegated,  the  calyx  and  corolla 
both  being  deeply  bilabiate.  Only  the  two  anterior  stamens  are 
fertile  (bear  anthers)  ;  the  connective  is  transverse,  the  upper 
end  bearing  a  perfect  pollen-sac,  and  the  lower  a  somewhat 
enlarged  rudimentary  pollen-sac  (Fig.  223,  F). 

Hedeoma  pulegioides  (American  pennyroyal)   (Fig.  371). 

MENTHA  species. — The  plants  are  nearly  glabrous,  diffusely 
branching  herbs,  which  form  leafy  stolons  that  are  perennial 
(Fig.  184).  The  leaves  and  flowering  tops  of  both  Mentha 
piperita  (Fig.  372)  and  Mentha  spicata  are  official. 

2.  VOLATILE  OILS  of  the  following  plants  are  official : 

Rosmarinus  officinalis  is  a  shrub  growing  in  the  Mediterranean 
countries.  The  plant  has  linear,  coriaceous  leaves,  and  bluish,  bila- 
biate flowers,  the  middle  lobe  of  the  lower  lip  of  the  corolla  being 
large,  concave,  and  toothed  on  the  margin.  The  flowering  tops 
yield  from  I  to  1.5  per  cent,  of  oil  which  is  composed  of  15  to  18 
per  cent,  of  borneol;  about  5  per  cent,  of  bornyl  acetate;  and 
pinene,  camphene,  camphor,  and  cineol.  There  are  two  commer- 
cial varieties  of  the  oil,  the  Italian  and  French,  the  latter  having 
the  finer  odor. 

Lavandula  offlcinalis  (garden  lavender)  is  a  shrub  growing  in 
the  Northern  Mediterranean  countries,  as  well  as  in  England. 
The  leaves  are  linear,  coriaceous ;  the  flowers  are  small,  light  blue, 
bilabiate,  with  a  tubular  calyx,  and  occur  in  opposite  cymes 
(verticillasters). 

The  oil  is  derived  from  the  fresh  flowering  tops,  the  flowers 
yielding  about  0.5  per  cent.  Two  kinds  of  oil  are  on  the  market, 
namely,  French  and  English.  The  French  oil  contains  30  to  45 
per  cent,  of  1-linalyl  acetate;  linalool;  geraniol,  both  of  which 
latter  constituents  occur  free  and  as  esters.  The  English  oil  con- 
tains about  5  to  10  per  cent,  of  linalyl  acetate  and  a  slight  amount 
of  cineol.  Spike  lavender  (Lavandula  Spica)  is  sometimes  dis- 
tilled with  true  lavender  (see  p.  679). 


CLASSIFICATION  OF  ANGIOSPERMS. 


677 


FlG.  371.  American  Pennyroyal  (Hedeoma  pulegioides),  a  low,  annual  plant,  growing 
in  dry  soil;  having  small,  opposite,  elliptical  leaves;  and  loose  clusters  of  bilabiate  flowers, 
often  forming  terminal  leafy  racemes. — Bureau  of  Plant  Industry,  U.  S.  Department  of 
Agriculture. 

Thymus  vulgaris  (garden  thyme)  is  a  small  shrub  having 
linear  or  linear-lanceolate  leaves,  and  pale  blue  flowers  with 


678 


A  TEXT-BOOK  OF  BOTANY. 


strongly  bilabiate,  hairy  calyx,  and  occur  in  axillary  cymes.    The 
plant  grows  in  the  mountains  of  Southern  France.     The  herb 


FIG.  372.  Peppermint  (Mentha  piperita):  B,  portion  of  shoot  showing  petiolate  leaves; 
C,  transverse  section  of  leaf  showing  several  forms  of  glandular  hairs  on  lower  surface, 
loose  parenchyma  (m)  and  palisade  cells  (p) ;  D,  lower  surface  of  leaf  showing  stoma  (s)  and 
glandular  hair  (g).  Spearmint  (Mentha  spicatd) :  A,  portion  of  shoot  showing  flowers  and 
nearly  sessile  leaves;  E,  flower;  F,  outspread  corolla  showing  cleft  posterior  lobe  (p)  and 
the  four  adnate,  included  stamens;  G,  H,  hairs  from  calyx;  I,  sphere  crystals  (sphaerites)  of 
a  carbohydrate  found  in  the  corolla  and  style;  J,  pollen  grains. 

contains  from  0.3  to  0.9  per  cent,  of  volatile  oil,  which  is  of  a 
dark  reddish-brown  color,  and  contains  from  20  to  25  per  cent,  of 
thymol ;  and  cymene,  1-pinene,  borneol  and  linalool.  The  Spanish 


CLASSIFICATION  OF  ANGIOSPERMS.  679 

oil  of  thyme  contains  from  50  to  70  per  cent,  of  carvacrol,  but  no 
thymol. 

3.  OF  OTHER  PLANTS  OF  THE  LABIATE  which  are  of  interest, 
the  following  may  be  mentioned : 

Lavandula  Spica  yields  oil  of  spike,  which  has  an  odor  of 
lavender  and  rosemary.  The  oil  contains  camphor,  borneol,  cineol, 
linalool,  and  camphene. 

Origanum  Majorana  (Sweet  marjoram)  is  an  annual  culti- 
vated herb  that  has  more  or  less  oval,  entire  leaves,  white  flowers, 
and  an  aromatic  odor  and  taste.  It  produces  a  volatile  oil  which 
contains  terpinene  and  d-terpineol.  Origanum  vulgar e  (Wild 
marjoram)  grows  in  fields  and  waste  places  in  the  Eastern  United 
States  and  Canada.  The  calyx  is  equally  5-toothed  and  the 
corolla  varies  from  white  to  pink  or  purple.  It  contains  a  volatile 
oil  having  an  odor  somewhat  like  that  of  the  oil  of  O.  Majorana. 
Origanum  hirtum  and  O.  Onites  yield  an  origanum  oil  containing 
carvacrol  and  cymene.  The  oils  obtained  from  Cretian  Origanum 
are  the  source  of  commercial  carvacrol. 

Pogostemon  Patchouli,  a  plant  cultivated  in  Southern  China 
and  the  East  and  West  Indies,  furnishes  the  oil  of  PATCHOULI 
used  in  perfumery.  Patchouly  camphor  and  cadinene  have  been 
isolated  from  the  oil,  but  nothing,  however,  appears  to  be  known 
of  the  nature  of  the  odorous  principle. 

Hyssopus  officinalis  (Garden  hyssop)  contains  about  0.5  per 
cent,  of  volatile  oil  to  which  the  characteristic  odor  of  the  plant 
is  due.  Satureia  hortemis  (summer  savory)  yields  a  volatile  oil 
containing  carvacrol,  cymene  and  terpene.  Ocimum  Basilicum 
(Sweet  basil)  is  an  herb  growing  in  Europe,  and  yields  an  oil 
which  is  used  in  the  preparation  of  Chartreuse  and  similar  liquors. 
The  oil  contains  methyl  chavicol,  linalool,  cineol,  camphor,  pinene, 
and  terpin  hydrate. 

Melissa  officinalis  (Sweet  balm)  is  a  perennial  herb  indigenous 
to  Europe  and  Asia  and  also  cultivated.  The  leaves  are  ovate, 
dentate,  and  the  flowers  are  bilabiate,  the  calyx  being  bell-shaped 
and  13-nerved.  The  taste  is  bitter,  this  being  due  to  a  bitter 
principle.  The  fresh  leaves  are  quite  aromatic  and  produce  from 
o.i  to  0.25  per  cent,  of  a  volatile  oil  containing  a  stearoptene. 

Several  species  of  Monarda  known  as  HORSEMINT  or  wild 


68o 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  373.  Cat  Mint  or  Catnip  (Nepeta  Cataria),  a  hardy  perennial  herb  with  heart- 
shaped,  oblong,  deeply  crenate,  velvety,  whitish  green  leaves,  bearing  in  the  axils  dense 
whorls  of  light  purplish  flowers.  It  is  a  common  weed  and  derives  its  common  name  from 
the  fact  that  cats  are  fond  of  it,  eating  it  and  rubbing  themselves  upon  it. — Bureau  of  Plant 
Industry,  U.  S.  Department  of  Agriculture. 

bergamot  are  used  in  medicine.     The  oil  was  at  one  time  official. 
The  oil  of  Monarda  punctata,  a  perennial  herb  found  growing 


CLASSIFICATION  OF  ANGIOSPERMS. 


681 


from  New  York  to  Texas,  contains  thymol,  thymoquinone,  hydro- 
thymoquinone,  carvacrol,  cymene,  and  limonene. 

Nepeta  Cataria   (catnip)   is  a  perennial  herb  naturalized  in 
the  United  States  from  Europe  (Fig.  373).    It  contains  a  bitter 


FlG.  374.     (b)  A  mass  of  Ground  Ivy  (Nepeta  hederacea)   growing  on  an  embankment, 
with  (a)  Spring  Beauty  (Claytonia  virginica). 

principle,  tannin,  and  an  oxygenated  volatile  oil.  Nepeta  hede- 
racea or  GROUND  IVY  is  a  creeping  perennial  herb  with  blue  bilabi- 
ate flowers  and  reniform  leaves  (Fig.  374).  It  contains  a  bitter 
principle  and  volatile  oil.  Cunila  origanoides,  or  American  DIT- 


682 


A  TEXT-BOOK  OF  BOTANY. 


TANY,  is  a  small  perennial  herb  growing   from   New  York  to 
Florida,  and  characterized  by  its  pungent  aromatic  properties. 

Leonurus  Cardiaca  or  MOTHERWORT  is  a  perennial  herb  nat- 
uralized in  the  United  States  and  Canada  from  Europe.     The 


FIG.  375.  Flowering  tops  of  Datura  fastuosa  flava,  a  variety  of  a  plant  growing  in  the 
East  Indies,  the  Malay  Archipelago,  and  tropical  Africa,  containing  much  the  same  con- 
stituents as  Datura  Stramonium. — After  Newcomb. 


leaves  are  3-lobed;  the  calyx  is  5-nerved  and  with  5  prickly 
teeth ;  the  corolla  varies  from  white  to  pink  or  purple.  The  plant 
contains  a  volatile  oil  of  rather  an  unpleasant  odor ;  a  bitter  prin- 
ciple; two  resins  and  several  organic  acids,  namely,  malic,  citric 
and  tartaric. 


CLASSIFICATION  OF  ANGIOSPERMS. 


683 


/.  SOLANACE^:  OR  POTATO  FAMILY.— The  family 
includes  herbs,  shrubs,  trees,  and  vines,  which  are  most  abundant 
in  tropical  regions.  The  leaves  are  alternate  and  vary  from  entire 


• 


FIG.  376.     Atropa  Belladonna  showing  the  alternate,  petiolate,  ovate,  entire  leaves, 
in  the  axils  of  which  are  the  solitray  fruits  or  flowers  with  large,  leafy  bracts. 

to  dissected.  The  flowers  are  mostly  regular,  except  in  hyos- 
cyamus.  The  stamens  are  adnate  to  the  corolla  tube,  the  anthers 
connivent,  and  the  pollen-sacs  apically  or  longitudinally  dehiscent. 
The  fruit  is  a  berry  or  capsule  in  which  the  sepals  mostly  persist 


.684  A  TEXT-BOOK  OF  BOTANY. 

and  sometimes  become  enlarged  or  inflated.     The  seeds  have  a 
large  reserve  layer,  and  the  embryo  is  frequently  curved. 

Datura  Stramonium  (Jimson  weed,  thorn  apple)  is  a  large, 
annual,  branching  herb,  found  in  waste  places  in  the  United  States 
and  parts  of  Canada,  being  naturalized  from  Asia.  The  leaves 
and  flowering  tops  are  official.  The  large,  spiny  capsule  is  shown 
in  Fig.  236,  B.  D.  fastuosa  (Fig.  375)  has  similar  medicinal 
properties. 

Atropa  Belladonna  (Deadly  nightshade)  is  a  perennial  herb 
producing  a  large,  fleshy  root,  which  is  used  in  medicine  (Fig. 
376),  as  are  also  the  leaves  and  flowering  tops. 

Scopolia  carniolica  is  a  perennial  herb  with  nearly  entire  or 
somewhat  irregularly  toothed  leaves.  The  flowers  are  campan- 
ulate  and  dark  purple.  The  fruit  is  a  globular,  transversely  dehis- 
cent capsule  (pyxidium). 

Hyoscyamus  niger  or  henbane  is  a  biennial  herb  (Fig.  377) , 
the  leaves  and  flowering  tops  of  which  are  official. 

Pichi  is  the  dried  leafy  twigs  of  Fabiana  imbricata,  a  shrub 
with  small,  scale-like  leaves,  indigenous  to  Chile.  It  contains  a 
volatile  oil;  o.i  per  cent,  of  a  bitter  alkaloid ;  a  glucoside  resem- 
bling aesculin ;  and  a  bitter  resin. 

Solatium  Dulcamara  (Bitter  sweet)  is  a  perennial,  climbing 
herbaceous  plant,  indigenous  to  Europe  and  Asia  and  naturalized 
in  the  Northern  United  States.  The  branches  which  have  begun 
to  develop  periderm  are  collected,  and  were  formerly  official  as 
DULCAMARA.  They  are  cut  into  pieces  10  to  20  mm.  long  which 
are  greenish-brown,  hollow,  with  a  sweetish,  bitter  taste  and 
contain  a  glucoside,  dulcamarin,  and  the  gluco-alkaloid  solanine 
(Fig.  378). 

Solanum  carolinense  (Horse  nettle)  is  a  perennial  herb  having 
numerous  yellow  prickles  on  the  branches  and  leaves.  The  leaves 
are  oblong  or  ovate,  irregularly  lobed  (Fig.  379).  The  flowers 
are  white  or  light  blue  and  occur  in  lateral  cymes.  The  fruit  is 
an  orange-yellow,  glabrous  berry.  The  plant  is  common  in  waste 
places  in  Canada  and  the  United  States  east  of  the  Mississippi. 
The  root  and  berries  are  used  in  medicine.  The  root  is  simple 
and  quite  long,  5  to  10  mm.  in  diameter,  yellowish-brown,  the 
bark  readily  separating  from  the  wood.  It  has  a  narcotic  odor 


CLASSIFICATION  OF  ANGIOSPERMS. 


685 


377. 


Flowering  branch  of  Hyoscyamus  niger  annuum,  showing  sessile,  acutely  lobed 
leaves  and  two  of  the  funnel-form  flowers.  —  After  Newcomb. 


and  a  sweetish,  bitter,  somewhat  acrid  taste.  Both  the  root  and 
terries  contain  the  gluco-alkaloid  solanine,  which  varies  from 
0.15  (in  the  root)  to  0.8  per  cent,  (in  the  berries). 


686 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  378.  Bittersweet  (Solanum  Dulcamara),  a  perennial,  climbing  or  twining  shrub, 
with  several  types  of  leaves,  varying  from  ovate  heart-shaped.  The  flowers  are  blue  or 
purplish  and  hang  in  loose  cymose  clusters.  The  fruit  is  an  ovoid,  reddish  berry  and  very 
poisonous.  It  is  sometimes  eaten  by  children,  producing  fatal  effects. — After  Brown. 


CLASSIFICATION  OF  ANGIOSPERMS. 


687 


Capsicum  fastigiatum  (Cayenne  pepper)  is  a  perennial,  smooth, 
herbaceous,  or  somewhat  shrubby  plant,  with  ovate,  acuminate, 
petiolate,  entire  leaves ;  the  flowers  are  greenish-white,  and  solitary 


K 


FIG.  379.  Horse  nettle  (Solatium  ca,rolinpnseV  A,  portion  of  shoot  showing  flowers 
and  fruits  and  spines  on  leaves  and  stem;  B,  longitudinal  section  of  spine  (s)  and  portion 
of  stem  showing  glandular  (g)  and  non-glandular  (h)  hairs,  and  cells  containing  small 
sphenoidal  crystals  (ca) ;  C,  thick-walled,  strongly  lignified  cells  of  spine;  D,  portion  of 
fibrovascular  bundle  showing  small  sphenoidal  crystals  (ca)  of  calcium  oxalate  in  the  cells 
accompanying  the  sieve;  E,  stellate,  non-glandular  hair;  F,  stbma  of  stem;  G,  diagram  cf 
cross  section  of  flower  showing  sepals  (s),  petals  (p),  stamens  (a),  ovary  (c);  H, longitudinal 
section  of  flower;  I,  stamen  showing  terminal  pores;  J,  cross  section  of  2-locular  berry; 
K,  pollen  grains,  30  M  in  diameter. 

in  the  axils  of  the  leaves.  The  fruit  is  official  and  is  known  in 
commerce  as  African  or  Cayenne  pepper.  This  plant  and  a  num- 
ber of  other  species  of  Capsicum  are  indigenous  to  tropical 


688  A  TEXT-BOOK  OF  BOTANY. 

America,  where  they  are  extensively  cultivated,  as  also  in  Africa 
and  India. 

Nicotiana  Tabacum  (Virginia  Tobacco  plant)  is  a  tall  annual 
herb  indigenous  to  tropical  America  and  widely  cultivated.  The 
stem  is  simple,  giving  rise  to  large,  pubescent,  ovate,  entire,  decur- 
rent  leaves,  the  veins  of  which  are  prominent  and  more  or  less 
hairy.  The  flowers  are  long,  tubular,  pink  or  reddish,  and  occur  in 
terminal  spreading  cymes.  The  various  forms  of  tobacco  are 
made  from  the  leaves,  which  are  hung  in  barns,  whereby  they 
undergo  a  slow  drying  or  process  of  curing.  Other  species  of 
Nicotiana  are  also  cultivated,  as  N.  persica,  which  yields  Persian 
tobacco ;  and  N.  rustica,  the  source  of  Turkey  tobacco.  Tobacco 
leaves  contain  from  0.6  to  9  per  cent,  of  the  alkaloid  nicotine ;  an 
aromatic  principle  nicotianin  or  tobacco  camphor,  to.  which  the 
characteristic  flavor  is  due  and  which  is  formed  during  the  curing 
of  the  leaves.  The  dried  leaves  yield  from  14  to  15  per  cent,  of 
ash,  consisting  in  large  part  of  potassium  nitrate. 

Solanuvn  tuberosum  (Potato  plant)  is  indigenous  to  the  Andes 
region  of  South  America  and  is  extensively  cultivated  on  account 
of  the  edible  tubers.  The  tubers  (potatoes)  contain  about  75  per 
cent,  of  water,  20  per  cent,  of  starch,  and  nearly  2  per  cent,  of 
proteins  in  the  form  of  large  protein  crystalloids.  The  fruits  and 
young  shoots  contain  the  gluco-alkaloid  solanine  and  the  alkaloid 
solanidine.  The  tubers  contain  a  small  amount  of  solanine,  which 
is  increased  when  they  are  attacked  by  certain  fungi  or  exposed 
to  light.  (Consult  pp.  142,  148,  194,  and  198.) 

Besides  the  potato  plant,  several  other  plants  belonging  to  the 
Solanaceae  yield  vegetables,  as  the  Tomato  plant  (Solanuin  Lyco- 
persicum)  and  the  Egg  plant  (Solanum  Melongena).  Various 
cultivated  species  of  Capsicum  annuum  furnish  the  common  red 
peppers  of  the  market. 

g.  SCROPHULARIACE^  OR  FIGWORT  FAMILY.— 
The  plants  are  herbs,  shrubs  or  trees  with  opposite  or  alternate 
leaves  and  perfect,  mostly  complete  and  irregular  flowers.  The 
corolla  and  stamens  show  some  resemblance  to  those  of  the  Labi- 
atse  in  that  the  corolla  is  frequently  more  or  less  2-lipped  and  the 
stamens  are  didynamous.  The  fruit  is  a  dehiscent  capsule  and 


CLASSIFICATION  OF  ANGIOSPERMS.  689 

the  seeds  have  a  reserve  layer  and  a  straight  or  slightly  curved 
embryo.   , 


FIG.  380.   Culver's-root  (Leptandra  virginica)  showing  the  verticillate  leaves  and  the  long 
spike-like  terminal  racemes. 

Leptandra  virginica  (Veronica  virginica),  or  Culver's  root,  is 
a  perennial  herb  with  leaves  in  whorls  of  3  to  9,  those  on  the  upper 
part  of  the  stem  being  opposite.  They  are  lanceolate,  serrate, 

44 


690 


A  TEXT-BOOK  OF  BOTANY. 


and  pinnately  veined ;  the  flowers  are  white  or  bluish,  tubular,  and 
in  dense  racemes.    The  rhizome  and  roots  are  official  (Fig.  380). 


PIG.  381.  Foxglove  (Digitalis  purpurea):  The  terminal  i-sided  raceme  with  slightly 
irregular,  declined,  tubular  flowers,  and  a  leaf  of  the  first  year's  plant  with  long,  winged 
or  laminate  petiole. 

Digitalis  purpurea  (Foxglove)  is  a  tall,  biennial,  pubescent 
herb,  producing  the  first  year  a  large  number  of  basal  leaves 
(Fig.  381),  and  the  second,  a  long  raceme  of  drooping,  tubular, 


CLASSIFICATION  OF  ANGIOSPERMS.  691 

slightly  irregular,  purplish  flowers ;  the  inner  surface  of  the  corolla 
is  spotted,  the  stamens  are  didynamous,  and  the  upper  calyx 
segment  is  narrower  than  the  others.  The  leaves  are  official  in  all 
the  pharmacopoeias. 

The  Scrophulariacese  are  well  represented  in  the  United  States, 
and  a  number  of  the  plants  have  medicinal  properties.  The  com- 
mon MULLEIN  (Verbascum  Thapsus)  contains  a  volatile  oil, 
two  resins,  and  a  bitter  principle.  The  flowers  of  mullein  contain 
the  same  principles  and  in  addition  a  yellow  coloring  principle. 
Other  species  of  Verbascum  are  used  in  medicine  in  different 
parts  of  the  world. 

BUTTER-AND-EGGS  (Linaria  vulgaris)  contains  a  crystalline 
principle,  linariin,  antirrhinic  acid,  a  volatile  oil,  resin,  and  tannin. 
Several  species  of  Scrophularia,  as  S.  nodosa  of  Europe  and  S. 
marilandica  of  the  Eastern  United  States,  contain  a  pungent 
resin  and  a  trace  of  an  alkaloid.  TURTLE-HEAD  (Chelone  glabra] 
(Fig.  382)  contains  a  bitter  principle  and  gallic  acid.  The  plant  of 
HYSSOP  (Gratiola  officinalis)  of  Europe  contains  gratiolin,  a  bitter 
glucoside,  and  gratiosolin.  The  leaves  of  Curanga  amara  of  the 
East  Indies  contain  a  glucoside,  curanjiin,  which  resembles  digi- 
talin  in  its  action. 

h.  BIGNONIACE;E  OR  TRUMPET-CREEPER  FAM- 
ILY.— The  plants  are  shrubs,  trees  or  woody  vines,  and  are  repre- 
sented in  the  United  States  by  the  catalpa  tree  (Catalpa  bigno- 
nioides)  and  the  trumpet  creeper  (Tecoma  radicans).  The  bark, 
pods,  and  seeds  of  CATALPA  have  been  used  in  medicine  and  con- 
tain a  bitter  principle,  catalpin,  a  glucoside,  and  several  crystalline 
principles.  The  TRUMPET  CREEPER  contains  narcotic  poisonous 
principles.  The  leaflets  of  CAROBA  (Jacaranda  Copaia)  and  other 
species  of  Jacaranda  contain  the  alkaloid  carobine,  an  aromatic 
resin,  carobone,  and  a  principle  having  the  odor  of  coumarin. 

i.  PEDALIACE^:.— The  plants  are  herbs  indigenous  to  the 
Tropics  of  the  Old  World,  some  of  which  are  now  cultivated  in 
the  Tropics  of  both  hemispheres.  Benne  oil  (oil  of  sesame)  is 
obtained  from  the  seeds  of  Sesamum  indicum  by  expression.  It 
consists  chiefly  of  a  glycerite  of  oleic  acid,  a  glycerite  of  linoleic 
acid,  and  myristin,  palmitin,  and  stearin.  It  is  a  bland,  non-drying 
oil  and  is  used  like  olive  oil. 


692 


A  TEXT-BOOK  OF  BOTANY. 


PIG.  382.  Turtle-head  (Chelone  glabra),  a  perennial  herb  with  lanceolate,  serrate, 
opposite  leaves  and  short,  terminal  spikes  of  whitish  or  purplish  flowers.  The  corolla  is 
bilabiate,  the  mouth  slightly  open,  the  upper  lip  broad  and  arched,  suggesting  the  head  of 
a  turtle  or  snake,  hence  the  origin  of  the  common  name. — Bureau  of  Plant  Industry,  U.  S. 
Department  of  Agriculture. 


CLASSIFICATION  OF  ANGIOSPERMS.  693 


FIG.  383.     Purple  Gerardia  (Gerardia  Purpurea,  Fam.  Scrophulariaceae) ,  a  branching  herb 
with  linear  leaves;  and  large,  bright  purplish-pink,  bilabiate  flowers. — After  Brown. 


694 


A  TEXT-BOOK  OF  BOTANY. 


/.  ACANTHACE^;     OR     ACANTHUS     FAMILY.— The 
plants  are  mostly  tropical  perennial  herbs,  or  shrubs  with  opposite 


TlG.  384.  Common  Plantain  (Plantago  major).  A  very  familiar  weed  found  along 
waysides  and  in  poorly  kept  lawns.  The  leaves  are  clustered,  lying  near  the  ground,  broadly 
elliptical  and  with  prominent  parallel  veins.  The  flowers  occur  in  long,  dense  spikes  which 
give  rise  to  small,  capsular  fruits,  being  sometimes  employed  as  a  green  bird  food. — After 
Brown. 

leaves ;  in  the  mesophyll  or  epidermal  cells  and  parenchyma  of  the 
axis  occur  cystoliths.  Several  genera  are  represented  in  the 
United  States,  one  of  which,  Ruellia  (Ruellia  ciliosa),  is  the  source 


CLASSIFICATION  OF  ANGIOSPERMS. 


695 


PIG.  385.  Squaw-root,  also  known  as  Cancer-root  (Conopholis  americana),  one  of  the 
OrobanchacecE  or  root  parasites.  It  is  shown  here  growing  on  the  roots  of  another  plant. 
The  flowering  plants  are  from  i  to  2  dm.  high,  and  consist  of  a  cone-like  stalk  with  fleshy 
scales  surmounted  by  a  spike  of  more  or  less  yellowish  flowers. — After  Troth. 


696  A  TEXT-BOOK  OF  BOTANY. 

of  the  spurious  spigelia  which  has  been  on  the  market  for  some 
years  past. 

Ruellia  ciliosa  is  a  perennial  herb  which  is  distinguished  from 
the  other  species  of  the  genus  Ruellia  by  the  leaves,  stems,  and 
calyx  being  distinctly  pubescent.  The  leaves  are  ovate-lanceolate, 
nearly  sessile  and  entire;  the  flowers  are  blue,  sessile,  solitary,  or 
two  or  three  in  a  cluster,  in  the  axils  of  the  leaves ;  the  stamens 
are  4,  and  exserted.  The  fruit  is  an  oblong,  terete  capsule  con- 
taining from  6  to  20  orbicular  seeds.  The  plant  is  found  from 
New  Jersey  and  Pennsylvania  to  Michigan  and  as  far  south  as 
Florida  and  Louisiana.  Long  cystoliths  are  found  in  some  of  the 
epidermal  cells  of  both  surfaces  of  the  leaf. 

Quite  a  number  of  the  plants  of  the  Acanthacese  are  used  in 
the  Tropics  in  medicine.  One  of  these,  Adhatoda  Vasica  of  trop- 
ical Asia,  contains  the  alkaloid  vasicine,  and  is  said  to  have  the 
property  of  destroying  algae  which  grow  in  the  rice  swamps. 

k.  PLANTAGINACE^:  OR  PLANTAIN  FAMILY.— The 
plants  are  annual  or  perennial  herbs,  represented  by  but  few 
genera,  but  numerous  species.  The  principal  genus  is  Plantago, 
which  includes  200  species  that  are  widely  distributed.  Several 
species  of  Plantago  are  used  in  medicine.  The  common  plantain 
(Plantago  major)  contains  a  glucoside,  acubin;  emulsin;  and 
invertin,  and  the  short  rhizome,  considerable  starch.  The  seed- 
coat  has  an  outer  mucilaginous  layer,  and  the  mucilage  of  the 
seeds  of  Plantago  Psyllium,  P.  arenaria  (both  of  Europe),  and 
P.  Ispaghula  (of  the  East  Indies)  is  used  as  a  sizing  material. 
The  seeds  of  a  number  of  the  species  of  Plantago  are  used  as 
bird  food,  particularly  for  canaries. 

/.  OROBANCHACE^:  OR  BROOM-RAPE  FAMILY.— 
This  very  interesting  family  is  made  up  of  plants  which  are 
parasitic  upon  the  roots  of  other  plants  and  are  consequently 
rather  light  in  color,  as  they  develop  no  chlorophyll.  Squaw-root 
or  Cancer-root  (Conopholis  americana)  has  the  flowers  arranged 
in  the  form  of  a  spike  looking  like  an  elongated  cone,  especially 
after  the  flowers  have  begun  to  turn  brown  (Fig.  385).  Another 
little  plant,  also  more  or  less  white  or  yellow  in  color,  is  Beech- 
drops  (Epifagus),  which  develops  upon  the  roots  of  the  beech. 


CLASSIFICATION  OF  ANGIOSPERMS.  697 

VI.    ORDER  RUBIALES. 

The  plants  of  this  order  are  distinguished  from  all  of  the 
preceding  Sympetalae  by  having  flowers  which  are  distinctly  epigy- 
nous.  The  leaves  are  opposite  or  verticillate. 

a.  RUBIACE^  OR  MADDER  FAMILY.— The  plants  are 
herbs,  shrubs,  or  trees,  and  of  the  representatives  found  in  the 
United  States  the  following  may  be  mentioned:  Bluets  (Hous- 


PIG.  386.     Cinchona  Ledgeriana:  A,  flowering  branch;  B,  bud  and  open  flower; 
C,  fruiting  branch. — After  Schumann. 

tonia  species),  Partridge-berry  (Mitchella  re  pens),  and  Bedstraw 
(Galium  species).  In  Mitchella  and  Houstonia  the  flowers  are 
dimorphic. 

CINCHONA  species. — The  plants  are  mostly  trees,  or  rarely 
shrubs,  with  elliptical  or  lanceolate,  entire,  evergreen,  petiolate, 
opposite  leaves  (Fig.  386).  The  flowers  are  tubular,  rose-colored 
or  yellowish-white,  and  occur  in  terminal  racemes.  The  fruit  is 
a  capsule,  which  dehisces  into  two  valves  from  below  upward, 
the  valves  being  held  above  by  the  persistent  calyx.  The  seeds 


698 


A  TEXT-BOOK  OF  BOTANY. 


CLASSIFICATION  OF  ANGIOSPERMS. 


699 


are  numerous  and  winged.  There  are  from  30  to  40  species  of 
Cinchona  found  growing  in  the  Andes  of  South  America  at  an 
elevation  above  800  M.  in  a  restricted  area  about  500  miles  in 
length  extending  from  Venezuela  to  Bolivia.  The  plants  are 


FIG.  388.  Ipecac  plant  \Cephaelis  (Uragoga)  Ipecacuanha]:  A,  flowering  shoot;  B, 
flower hrlongitudinal  section ;  C,  fruit;  D,  fruit  in  transverse  section;  E.seed;  F,  annulate 
root. — After  Schumann. 

cultivated  in  Java,  Ceylon,  New  Zealand,  and  Australia,  as  well 
as  in  Jamaica  (Fig.  387). 

There  are  two  species  which  furnish  the  Cinchona  bark  of 
medicine:  (i)  Cinchona  Ledgeriana  (C.  Calisaya  Ledgeriana) , 
which  has  small,  elliptical,  coriaceous  leaves,  the  under  surface 
o!  which  is  reddish ;  small,  yellowish,  inodorous  flowers,  and  a 


700  A  TEXT-BOOK  OF  BOTANY. 

short  capsule;  (2)  C.  succirubra,  which  has  large,  thin,  broadly- 
elliptical  leaves,  purplish-red  calyx,  rose-colored  petals,  and  a 
very  long  capsule.  •  While  C.  Ledgeriana  yields  barks  containing 
the  highest  amount  of  alkaloids,  C.  succirubra  is  most  cultivated. 

Uragoga  (Cephaclis)  Ipecacuanha. — The  plants  are  perennial 
herbs  10  to  20  cm.  high,  with  a  creeping,  woody,  hypogeous  stem. 
The  roots  are  official  in  all  of  the  pharmacopoeias  (see  Vol.  II). 
The  leaves  are  elliptical,  entire,  short-petiolate,  and  with  divided 
stipules  (Fig.  386).  The  flowers  are  white  and  form  small  ter- 
minal heads.  The  fruit  is  a  blue  berry,  with  characteristic  spiral 
arrangement  of  the  carpels. 

Coffea  arabica  is  a  small  evergreen  tree  or  shrub  with  lanceo- 
late, acuminate,  entire,  slightly  coriaceous,  dark  green,  short- 
petiolate  leaves,  which  are  partly  united  with  the  short  inter- 
petiolar  stipules  at  the  base.  The  flowers  are  white,  fragrant,  and 
•  occur  in  axillary  clusters.  The  fruit  is  a  small,  spherical  or  ellip- 
soidal drupe  with  two  locules,  each  containing  one  seed,  or  COFFEE 
GRAIN.  The  coffee  plant  is  indigenous  to  Abyssinia  and  other 
parts  of  Eastern  Africa,  and  is  cultivated  (Fig.  389)  in  tropical 
countries,  notably  in  Java,  Sumatra,  Ceylon,  and  Central  and  South 
America,  particularly  Brazil,  over  600,000  tons  being  produced 
annually  in  the.  latter  country.  The  yield  of  one  tree  is  between 
i  and  12  pounds.  There  are  two  methods  of'  freeing  the  seeds 
from  the  parchment-like  endocarp :  In  the  one  case  the  fruits 
are  allowed  to  dry  and  are  then  broken ;  in  the  other  case,  which 
is  known  as  the  wet  method,  the  sarcocarp  is  removed  by  means 
of  a  machine,  and  the  two  seeds  with  the  parchment-like  endocarp 
are  allowed  to  dry  in  such  a  manner  as  to  undergo  a  fermentation, 
and  after  drying  the  endocarp  is  removed.  Coffee  seeds  contain 
from  i  to  2  per  cent,  of  CAFFEINE  ;  from  3  to  5  per  cent,  of  tannin ; 
about  15  per  cent,  of  glucose  and  dextrin;  10  to  13  per  cent,  of  a 
fatty  oil  consisting  chiefly  of  olein  and  palmitin ;  10  to  13  per 
cent,  of  proteins ;  and  yield  4  to  7  per  cent,  of  ash.  The  official 
caffeine  is  derived  in  part  from  coffee  seeds. 

In  the  ROASTING  of  coffee  there  is  a  change  in  the  physical 
character  of  the  seeds,  as  well  as  a  change  in  some  of  the  constit- 
uents. The  AROMA  is  supposed  to  be  due  to  an  oil  known  as 
coffeol,  which  is  said  to  be  a  methyl  ether  of  saligenin. 


CLASSIFICATION  OF  ANGIOSPERMS. 


701 


FIG.  389.  Coffee  tree  growing  in  Costa  Rica.  An  evergreen  shrub,  with  elliptical 
leaves  resembling  somewhat  those  of  the  laurel.  The  flowers  are  white,  fragrant,  and  are 
formed  in  clusters  among  the  branches,  being  followed  by  the  berry-like  fruits,  which  when 
ripe  are  about  the  size  of  and  resemble  the  cranberry.  Each  fruit  contains  two  elliptical 
plano-convex  seeds,  which  on  being  separated  constitute  the  so-called  coffee  bean  of  com- 
merce.— Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 


702  A  TEXT-BOOK  OF  BOTANY. 

YOHIMBI  (Yohimbihi)  bark  is  obtained  from  Corynanthe  Yo- 
himbe,  a  tree  growing  in  the  Cameroon  region  of  Africa.  The 
pieces  of  bark  are  25  cm.  or  more  in  length,  5  to  8  mm.  thick, 
externally  dark  brown  or  grayish-brown,  and  somewhat  bitter. 
Numerous  bast  fibers  are  present,  but  no  sclerotic  cells.  It  yields 
4  alkaloids  (0.3  to  1.5  per  cent.),  the  principal  one  being  yohim- 
bine  (corymbine  or  corynine),  which  forms  white  prismatic 


FIG.  390.  Picking  coffee  in  Brazil.  The  coffee  shrub  is  cultivated  in  plantations,  and 
when  the  berries  are  ripe  they  are  collected  either  by  shaking  the  tree  and  allowing  the 
berries  to  fall  upon  a  cloth  or  they  are  picked  by  hand  directly  from  the  branches,  and 
removed  from  the  field  by  oxen  teams.  More  than  half  of  the  coffee  of  the  world  is  grown  in 
Brazil,  the  remainder  being  obtained  in  various  parts  of  tropical  America  and  East  India. — 
Reproduced  by  permission  of  The  Philadelphia  Commercial  Museum. 

needles,  soluble  in  alcohol  and  almost  insoluble  in  water,  and  on 
treatment  with  nitric  acid  becomes  first  deep  green  and  then 
yellowish,  changing  to  a  cherry-red  if  followed  with  an  alcoholic 
solution  of  potassium  hydroxide  (distinction  from  cocaine). 

A  number  of  the  Rubiaceae  contain  valuable  coloring  prin- 
ciples, as  the  madder  plant  (Rubia  tinctorum},  which  is  a  peren- 
nial herb  occurring  wild  in  Southern  Europe  and  formerly  culti- 
vated in  France  and  Germany  on  account  of  the  coloring  principle 


CLASSIFICATION  OF  ANGIOSPERMS.  703 


FIG.  391.  Buttonbush  (Cephalanthus  occidentalis) ,  a  small  shrub  growing  in  swamps 
and  along  streams  throughout  the  United  States.  The  leaves  are  opposite  or  whorled  in 
threes.  The  flowers  are  white  and  densely  aggregated  in  spherical  peduncled  heads;  they 
secrete  large  quantities  of  nectar,  and  are  sought  to  such  a  degree  by  the  bees  that  the 
bush  is  often  called  "Honey  balls."— After  Troth. 

in  its  roots.  The  root  is  known  commercially  as  MADDER,  and  con- 
tains when  fresh  a  yellow  coloring  principle,  which  on  the  drying 
of  the  root  breaks  up  into  several  glucosides,  one  of  which  on 
further  decomposition  yields  ALIZARIN,  the  principle  to  which  the 


704  A  TEXT-BOOK  OF  BOTANY. 

red  color  of  the  dried  root  is  due.  At  present  alizarin  is  made 
artificially  from  anthracene,  a  coal-tar  derivative. 

Morinda  citrifolia,  a  shrub  widely  distributed  in  tropical  coun- 
tries, contains  a  red  coloring  principle  in  the  flowers  and  a  yellow 
coloring  principle  in  the  roots,  the  latter  being  known  as  morindin 
and  resembling  the  color  principle  in  madder. 

The  pulp  of  the  fruit  of  Cape  jasmine  (Gardenia  jasminoides) 
contains  a  yellow  coloring  principle  resembling  crocin,  found  in 
Crocus. 

The  stem  and  root  barks  of  Button-bush  (Cephalanthus  occi- 
dentalis),  common  in  swampy  regions  in  the  United  States,  are 
used  in  medicine  (Fig.  391 ) .  The  barks  contain  a  bitter  glucoside, 
cephalanthin,  and  a  tasteless  glucoside  which  is  fluorescent  in  solu- 
tion. Mitchella  re  pens  contains  a  saponin-like  body  in  the  fruit 
and  a  tannin  and  bitter  principle  in  the  leaves.  Quite  a  number  of 
species  of  Galium  (bedstraw)  are  used  in  medicine  and  for  other 
purposes.  A  principle  resembling  glycyrrhizin  is  found  in  wild 
licorice  (Galium  circazans) ,  a  perennial  herb  growing  in  dry 
woods  in  the  United  States,  and  also  in  Galium  lanceolatum,  which 
is  found  from  Virginia  northward  to  Ontario.  The  yellow  bed- 
straw  (Galium  veruni),  naturalized  from  Europe,  contains  a  milk- 
curdling  ferment. 

b.  CAPRIFOLIACE^:  OR  HONEYSUCKLE  FAMILY.— 
The  plants  are  perennial  herbs,  shrubs,  trees,  or  woody  climbers 
with  opposite,  simple  or  pinnately  compound  leaves.  The  flowers 
are  perfect,  epigynous,  regular,  or  bilabiate,  and  arranged  in 
corymbs.  The  fruit  is  a  berry,  drupe,  or  capsule.  They  are  mostly 
indigenous  to  the  northern  hemisphere. 

Viburnum  prunifolium  (Black  haw)  is  a  shrub  or  small  tree 
25  cm.  in  diameter.  The  winter  buds  are  acute  and  reddish- 
pubescent  ;  the  leaves  are  ovate,  elliptical,  obtuse  or  acute  at  the 
apex,  somewhat  rounded  at  the  base,  finely  serrulate,  glabrous, 
and  short-petiolate  (Fig.  392)  ;  the  flowers  are  white  and  in 
nearly  sessile  cymes ;  the  fruit  is  a  small,  oval,  bluish-black, 
glaucous,  inferior  drupe.  The  root-bark  is  official. 

Viburnum  Opulus  (Wild  guelder-rose  or  cranberry-tree)  is 
a  shrub  about  half  the  height  of  V.  prunifolium,  with  broadly 
ovate,  deeply  3-lobed  and  coarsely  dentate  pubescent  leaves.  The 


CLASSIFICATION  OF  ANGIOSPERMS.  705 

flowers  are  white  and  in  compound  cymes,  the  outer  being  sterile 
and  large  and  showy.  The  fruit  is  a  reddish,  globular,  very 
acid  drupe,  clinging  to  the  branches  all  winter.  The  Snow-ball 
or  guelder-rose  of  the  gardens  is  a  sterile  variety  of  this  species. 
Another  variety  (edule)  is  also  cultivated  on  account  of  its  edible 
fruits,  particularly  in  Canada  and  the  Northern  United  States. 


FIG.  392.     Fruiting  branch  of  Viburnum  prumfolium. 

A  number  of  species  of  Viburnum  are  rather  common  in 
various  parts  of  the  United  States,  as  the  Maple-leaved  arrow- 
wood  (V .  acerifolium) ,  which  is  a  small  shrub  with  deeply 
3-lobed,  coarsely  dentate  leaves  and  small,  nearly  black  drupes ; 
Arrow-wood  (V .  dentatum),  with  broadly  ovate,  coarsely  den- 
tate leaves  and  blue  drupes,  which  become  nearly  black  when 
45 


;o6  A  TEXT-BOOK  OF  BOTANY. 

ripe;  Soft-leaved  arrow-wood  (V .  molle),  which  somewhat  re- 
sembles V.  dentatum,  but  has  larger  leaves  that  are  crenate  or 
dentate  and  stellate-pubescent  on  the  lower  surface ;  Larger  withe- 
rod  (V.  nudum),  having  nearly  entire  leaves  and  a  pink  drupe, 
which  becomes  dark  blue. 

Sambucus  canadensis  (American  elder)  is  a  shrub  growing 
in  moist  places  in  the  United  States  as  far  west  as  Arizona  and 
in  Canada.  The  leaves  are  5-  to  7-foliate,  the  leaflets  being  ovate, 
elliptical,  acuminate,  sharply  serrate,  and  with  a  short  stalk ;  the 
flowers  are  small,  white,  and  in  convex  cymes.  The  fruit  is  a 
deep  purple  or  black  berry-like  drupe.  The  dried  flowers  are  used 
in  medicine.  They  are  about  5  mm.  broad,  with  a  5-toothed, 
turbinate  calyx,  and  a  5-lobed,  rotate  corolla,  to  which  the  5  sta- 
mens are  adnate.  The  odor  is  peculiar  and  the  taste  is  muci- 
laginous and  somewhat  aromatic  and  bitter. 

The  active  principles  have  not  been  determined,  but  are  prob- 
ably similar  to  those  of  S.  nigra.  The  inner  bark  is  also  used  in 
medicine  and  contains  a  volatile  oil,  a  crystallizable  resin,  and 
valerianic  acid.  It  does  not  appear  to  contain  either  tannin  or 
starch.  The  roots  of  elder  contain  a  volatile  principle  somewhat 
resembling  coniine.  The  pith  consists  chiefly  of  cellulose,  is  deli- 
cate in  texture  and  has  a  variety  of  uses  (Fig.  132). 

The  Black  elder  (Sambucus  nigra),  which  is  a  shrub  com- 
mon in  Europe,  is  characterized  by  narrower  leaflets,  a  3-locular 
ovary,  and  black  berries.  The  flowers  are  official  in  some  of  the 
European  pharmacopoeias.  They  contain  about  0.4  per  cent,  of 
a  greenish-yellow,  semi-solid  volatile  oil,  which  when  diluted  has 
the  odor  of  the  flowers.  They  also  contain  an  acrid  resin. 

The  Red-berried  elder  or  mountain  elder  (S.  pub  ens)  some- 
what resembles  the  common  elder,  but  the  stems  are  woody,  and 
the  younger  branches  have  a  reddish  pith.  The  flowers  are  in 
paniculate  cymes,  and  the  fruits  are  scarlet  or  red. 

Other  plants  of  the  Caprifoliaceae  are  also  used  in  medicine. 
Horse  gentian  (Triosteum  perfoliatum),  a  perennial  herb  with 
connate-perfoliate  leaves  and  small,  orange-red,  globular  drupes, 
growing  in  Canada  and  the  United  States  as  far  west  as  Kansas, 
furnishes  the  drug  (rhizome)  known  as  WILD  IPECAC  or  Trios- 
teum. The  rhizome  is  yellowish-brown,  somewhat  branched, 


CLASSIFICATION  OF  ANGIOSPERMS.  707 

cylindrical,  10  to  20  cm.  long,  10  to  15  mm.  in  diameter,  with 
numerous  cup-shaped  stem-scars,  and  coarse,  spreading  roots; 
it  is  rather  hard  and  tough,  and  has  a  bitter,  nauseous  taste. 
Triosteum  contains  an  emetic  alkaloid,  triosteine,  and  considerable 
starch.  The  seeds  of  Triosteum  perfoliatum  are  sometimes  roasted 
and  employed  like  coffee,  the  plant  being  known  as  Wild  coffee. 
The  roots  and  stems  of  the  following  plants  are  sometimes 
employed:  The  Snowberry  (Symphoricarpos  racemosus),  the 
Bush  honeysuckle  (Diervilla  Lonicera),  and  various  species  of 
Lonicera,  these  being  also  known  as  honeysuckles. 

VII.  ORDER  VALERIANALES  OR  AGGREGATE. 

The  plants  are  mostly  herbs  with  an  inferior  ovary,  which  is 
either  unilocular  with  a  single  pendulous  ovule,  or  tri-locular 
with  frequently  but  a  single  anatropous  ovule. 

a.  VALERIANACE^E  OR  VALERIAN  FAMILY.— The 
plants  are  herbs  with  opposite,  exstipulate  leaves,  small,  perfect, 
or  polygamo-dioecious  flowers,  occurring  in  corymbs.  The  fruit 
is  dry,  indehiscent,  and  achene-like.  The  calyx  is  persistent,  be- 
coming elongated  and  plumose,  and  resembling  the  pappus  in  the 
Composite. 

Valeriana  officinalis  (Garden  or  Wild  valerian)  is  a  tall,  peren- 
nial herb,  more  or  less  pubescent  at  the  nodes.  The  leaves  are 
mostly  basal,  pinnately  parted  into  seven  or  more  segments,  which 
are  lanceolate,  entire,  or  dentate.  The  flowers  are  white  or  pink 
and  arranged  in  corymbed  cymes.  The  calyx  is  much  reduced, 
consisting  of  5  to  15  pinnately  branched  teeth  (pappus)  ;  the 
corolla  is  tubular,  somewhat  sac-like  on  one  side,  but  not  spurred 
as  in  other  members  of  this  family;  the  stamens  are  3  in  number 
and  adnate  to  the  corolla  tube ;  the  stigma  is  3-lobed.  The  fruit  is 
ovoid,  glabrous,  and  with  a  conspicuous  plumose  pappus.  The 
rhizome  and  roots  are  official. 

The  young  leaves  of  several  species  of  Valerianella  are  used 
as  a  salad  and  are  cultivated  like  spinach,  as  the  European  corn- 
salad  (V .  olitoria) ,  which  is  also  cultivated  to  some  extent  in 
the  United  States. 

b.  DIPSACACE;E  OR  TEASEL  FAMILY.— The  plants  are 

annual  or  perennial  herbs,  chiefly  indigenous  to  the  Old  World. 


;o8  A  TEXT-BOOK  OF  BOTANY. 

The  flowers  are  arranged  in  heads  on  a  common  torus,  resem- 
bling in  some  cases  those  of  the  Compositae. 

Some  of  the  plants  are  used  in  medicine,  as  the  roots,  leaves, 
flowers,  and  seeds  of  Fuller's  teasel  (Dipsacus  fullonum),  the 
roots  of  Succisa  pratensis  of  Europe,  and  several  species  of  Scabi- 
osa  and  Cephalaria.  The  seeds  of  Cephalaria  syriaca  when 
admixed  with  cereals  give  a  bread  that  is  dark  in  color  and  bitter. 
This  family  is,  however,  chiefly  of  interest  on  account  of  Fuller's 
teasel,  which  is  a  cultivated  form  of  Dipsacus  jerox,  indigenous 
to  Southwestern  Asia,  the  plant  being  cultivated  in  Europe  and 
New  York  State.  The  elongated,  globular  heads,  with  their  firm, 
spiny,  and  hooked  bracts,  are  used  in  the  fulling  of  cloth. 

VIII.    ORDER  CAMPANULAT^E. 

This  order  differs  from  the  two  preceding  by  having  the 
anthers  united  into  a  tube  (syngenesious).  It  includes  three  prin- 
cipal families,  which  are  distinguished  by  differences  in  the  char- 
acter of  the  androecium:  (a)  Cucurbitaceae,  in  which  there  are 
three  stamens,  having  not  only  the  anthers  united  but  the  fila- 
ments also  (monadelphous)  ;  (b)  Campanulacese,  in  which  there 
are  five  stamens,  both  the  filaments  and  anthers  being  united  into 
a  tube;  (c)  Compositse,  in  which  there  are  five  stamens,  but  the 
anthers  only  are  united,  the  filaments  being  separate  (Fig.  82,  A). 

a.  CUCURBITACE^:  OR  GOURD  FAMILY.— The  plants 
are  mostly  annual,  tendril-climbing  or  trailing  herbs  (Fig.  66), 
mainly  indigenous  to  tropical  regions.  The  leaves  are  alternate, 
being  opposite  the  tendrils,  petiolate,  and  entire,  palmately  lobed 
or  dissected.  The  flowers  are  epigynous ;  the  petals  are  borne  on 
the  calyx  tube  and  frequently  are  united  (campanulate)  ;  the  ovary 
is  i-  to  3-locular  and  with  few  or  many  anatropous  ovules.  The 
fruit  is  a  pepo,  which  is  indehiscent  but  may  burst  somewhat 
irregularly. 

Citrullus  Colocynthis  is  a  trailing  herb  with  deeply  lobed 
leaves.  The  flowers  are  yellow,  axillary,  and  monoecious,  the 
staminate  being  with  short  filaments  and  glandular  pistillodes 
(aborted  pistils),  and  the  pistillate  having  a  3-locular,  globose 
ovary  and  three  short  staminodes.  The  fruit  is  globular,  5  to  10 


CLASSIFICATION  OF  ANGIOSPERMS.  709 

cm.  in  diameter,  smooth,  greenish,  and  mottled.  The  fruit  de- 
prived of  the  epicarp  is  official. 

Cucurbita  Pepo  (pumpkin-vine)  is  an  extensively  trailing 
hispid  vine,  with  large,  nearly  entire,  cordate  leaves  having  long 
petioles.  The  tendrils  are  branching.  The  flowers  are  large, 
deep  yellow,  and  monoecious ;  the  staminate  ones  being  in  groups 
and  the  pistillate  single.  The  ffuit  is  a  large,  yellowish  berry, 
sometimes  weighing  from  10  to  72  K.  The  seeds  are  numerous 
and  are  official  as  Pepo. 

Ecballium  Elaterium  (Squirting  cucumber)  is  a  bristly-hairy, 
trailing  perennial  herb  with  thick,  rough-hairy,  cordate,  some- 
what undulate  leaves.  The  flowers  are  yellow,  monoecious.  The 
fruit  is  ellipsoidal,  about  4  cm.  long,  rough-hairy  or  prickly,  pend- 
ulous, and  at  maturity  separates  from  the  stalk,  when  the  seeds 
are  discharged  upward  through  a  basal  pore.  The  plant  is  indig- 
enous to  the  European  countries  bordering  the  Mediterranean, 
the  Caucasus  region,  Northern  Africa  and  the  Azores.  The  juice 
of  the  fruit  yields  the  drug  ELATERIUM,  which  is  official  in  the 
British  Pharmacopoeia.  Elaterium  yields  30  per  cent,  of  the 
ELATERIN  of  the  Pharmacopoeias.  From  the  latter  by  fractional 
crystallization  from  60  to  80  per  cent,  of  a-elaterin,  a  laevo-rota- 
tory  crystalline  substance  is  separated,  which  is  completely  devoid 
of  purgative  action ;  and  varying  amounts  of  /?-elaterin,  a  dextro- 
rotatory crystalline  compound  which  possesses  a  very  high  degree 
of  physiological  activity  (Power  and  Moore,  Ph.  Jour.,  29,  Oct. 
23,  1909,  p.  501 ;  and  Proc.  Chem.  Soc.,  No.  362,  1909,  p.  1985). 

Bryonia  or  BRYONY  is  the  dried  root  of  Bryonia  alba  (White 
bryony),  a  climbing  herb  indigenous  to  Southern  Sweden,  East- 
ern and  Central  Europe,  including  Southern  Russia,  and  Northern 
Persia  (Fig.  181).  The  root  contains  two  bitter  glucosides, 
bryonin  and  bryonidin ;  two  resinous  principles  and  considerable 
starch.  Bryonia  dioica  (Red  bryony)  also  has  medicinal  proper- 
ties and  is  a  source  of  the  drug.  B.  dioica  has  red  berries,  while 
the  fruit  of  B.  alba  is  black.  The  latter  plant  is  sometimes  known 
as  Black  bryony,  but  this  plant  should  not  be  confounded  with 
Tamus  communis  (Fam.  Dioscoreaceae),  of  Southern  Europe, 
the  rhizome  of  which  is  known  commercially  as  Black  bryony. 

The  fruits  and  seeds  of  various  members  of  the  Cucurbitacese 


710  A  TEXT-BOOK  OF  BOTANY. 

contain  powerful  drastic  and  anthelmintic  principles.  A  number 
/  of  the  plants,  however,  are  cultivated  on  account  of  the  fruits, 
which  are  used  as  food,  as  the  pumpkin  already  mentioned,  the 
WATER  MELON  ( Citrullus  vulgaris) ,  indigenous  to  Southern  Africa 
and  cultivated  in  Egypt  and  the  Orient  since  very  early  times ; 
CANTALOUPE  or  musk-melon,  derived  from  cultivated  varieties  of 
Cucumis  Melo,  indigenous  to  tropical  Africa  and  Asia,  also  culti- 
vated since  early  times.  The  common  CUCUMBER  is  obtained  from 
Cucumis  sativus,  which  is  probably  indigenous  to  the  East  Indies. 
These  fruits  contain  from  90  to  95  per  cent,  of  water,  and  the 
water  melon  contains  3.75  per  cent,  of  dextrose,  5.34  per  cent, 
of  saccharose,  and  yields  0.9  per  cent,  of  ash. 

Luffa  cylindrica  is  an  annual  plant  indigenous  to  the  Tropics 
of  the  Old  World.  It  is  cultivated  to  some  extent  in  America, 
but  especially  in  the  Mediterranean  region.  The  fruit  is  more  or 
less  cylindrical  and  20  cm.  or  more  long.  The  pulp  is  edible  and 
the  fibrovascular  tissue  forms  a  tough  network,  which,  when  the 
seeds,  epicarp,  and  pulpy  matter  are  removed,  constitutes  the 

LUFFA-SPONGE. 

The  fruits  of  Luffa  operculata  and  L.  echinata,  both  found  in 
Brazil,  contain  a  bitter  principle  resembling  colocynthin. 

b.  CAMPANULACE^E  OR  BELL-FLOWER  FAMILY.— 
The  plants  are  mostly  annual  or  perennial  herbs,  but  are  some- 
times shrubby,  with  an  acrid  juice  containing  powerful  alkaloids. 
The  rhizomes  and  roots  of  about  twelve  of  the  genera  contain 
inulin.  The  leaves  are  alternate ;  the  corolla  is  regular,  cam- 
panulate  and  rotate,  or  irregular,  as  in  Lobelia.  The  fruit  is  a 
capsule  or  berry  containing  numerous  small  seeds. 

Lobelia  infiata  (Indian  or  Wild  tobacco)  is  an  annual,  pubes- 
cent, branching  herb  (Fig.  224),  the  dried  leaves  and. tops  of 
which  are  official  (see  Vol.  II):  About  15  different  species  of 
Lobelia  are  used  in  medicine.  The  most  important  of  those  grow- 
ing in  the  United  States  is  the  Cardinal  flower  or  Red  lobelia 
{Lobelia  cardinalis),  a  plant  found  in  moist  soil  from  Canada  to 
Texas,  and  characterized  by  its  long,  compound  racemes  of  bright 
scarlet  or  red  flowers.  The  Blue  cardinal  flower  or  Blue  lobelia 
(L.  syphilitica)  is  a  plant  of  nearly  the  same  habit  and  same  gen- 


CLASSIFICATION  OF  ANGIOSPERMS.  711 

eral  character,  except  that  the  flowers  are  of  a  bright  dark  blue 
color  or  occasionally  white. 

c.  FAMILY  COMPOSITE.— This  is  a  large  group  of  plants, 
which  are  annual,  biennial,  or  perennial  herbs,  under-shrubs, 
shrubs,  trees  and  twiners  or  even  climbers,  a  few  being  aquatic. 
They  contain  inulin,  a  constituent  peculiar  to  this  group  of  plants. 
The  most  distinguishing  character  is  the  inflorescence,  which  is 
a  head  or  capitulum  (Fig.  228),  consisting  of  one  or  two  kinds 
of  flowers,  arranged  on  a  common  torus,  and  subtended  by  a 
number  of  bracts,  forming  an  involucre.  The  flowers  are  epigy- 
nous  and  the  fruit  is  an  achene,  usually  surmounted  by  the  per- 
sistent calyx,  which  consists  of  hairs,  bristles,  teeth  or  scales, 
which  are  known  collectively  as  the  PAPPUS  (Fig.  227). 

The  individual  flowers  are  called  florets  (Figs.  241,  242),  and 
may  be  hermaphrodite  or  pistillate,  monoecious,  dioecious,  or 
neutral.  Depending  upon  the  shape  of  the  corolla,  two  kinds  of 
flowers  are  recognized,  one  in  which  the  corolla  forms  a  tube, 
which  is  5-lobed  or  5-cleft,  known  as  TUBULAR  FLOWERS  (Figs. 
227,  228,  C)  ;  and  one  in  which  the  petals  are  united  into  a  short 
tube,  with  an  upper  part  that  forms  a  large,  strap-shaped,  usually 
5-toothed  limb,  known  as  LIGULATE  FLOWERS  (Figs.  227,  228,  D). 

In  some  of  the  plants  of  the  Compositse  the  head  consists  of 
ligulate  flowers  only,  but  in  the  larger  number  of  plants  the  head 
is  composed  of  both  tubular  and  ligulate  flowers  or  tubular  flowers 
alone  and  accordingly  two  main  groups  or  sub-families  are  dis- 
tinguished. The  sub-family  in  which  all  of  the  flowers  are  lig- 
ulate is  known  as  LIGULIFLOR^E,  or  CICHORIACE^:,  by  those  who 
give  the  group  the  rank  of  a  family.  This  group  includes  plants 
like  dandelion,  chicory,  lettuce,  and  Hieracium.  The  group  or 
sub-family  in  which  the  flowers  are  all  tubular  or  ligulate  on  the 
margin  only  is  known  as  the  TUBULIFLOR^E.  When  the  head 
consists  only  of  tubular  flowers  it  is  called  DISCOID,  but  when 
ligulate  flowers  are  also  present  it  is  called  RADIATE.  When  the 
heads  are  radiate,  as  in  the  common  daisy,  the  tubular  flowers 
are  spoken  of  as  DISK-FLOWERS,  and  the  ligulate  flowers  as  RAY- 
FLOWERS.  The  disk-flowers  are  usually  perfect,  while  the  ray- 
flowers  are  pistillate  or  neutral  (without  either  stamens  or  pistils). 
By  some  systematists  the  Tubuliflorae  are  divided  into  groups 


A  TEXT-BOOK  OF  BOTANY. 

which  have  been  given  the  rank  of  families.  This  division  is 
based  especially  on  the  characters  of  the  stamens.  In  a  small 
group  represented  by  the  ragweed  and  known  as  the  AMBROSI- 
ACE^E,  the  anthers,  while  close  together  (connivent) ,  are  not  united, 
and  the  corolla  in  the  marginal  or  pistillate  flowers  is  reduced  to  a 
short  tube  or  ring.  In  a  large  group,  which  includes  probably 
10,000  species  and  which  is  considered  to  be  the  COMPOSITE 
proper,  the  stamens  in  the  tubular  flowers  are  syngenesious  and 
the  marginal  or  ray-flowers  are  distinctly  ligulate.  This  group 
includes  the  daisy,  sunflower,  golden-rod,  aster,  thistle,  and  most 
of  the  plants  which  yield  official  drugs. 

It  may  also  be  added  that  the  Composite  is  considered  to  be 
the  highest  and  youngest  group  of  plants. 

Taraxacum  officinale  (Dandelion)  is  a  perennial,  acaulescent 
herb  with  milky  latex;  oblong-spatulate,  pinnatifid  or  runcinate, 
decurrent  leaves,  and  with  a  i -headed  scape,  the  stalk  of  which  is 
hollow.  The  flowers  are  ligulate,  golden-yellow  and  numerous; 
the  involucre  consists  of  two  series  of  bracts,  the  inner  one  of 
which  closes  over  the  head  while  the  fruit  is  maturing,  afterward 
becoming  reflexed.  The  fruit  consists  of  a  loose,  globular  head 
of  achenes,  each  one  of  which  is  oblong-ovate  and  with  a  slender 
beak  at  the  apex  which  is  prolonged  into  a  stalk  bearing  a  radiate 
tuft  of  silky  hairs,  which  constitute  the  pappus.  The  root  is  fusi- 
form and  usually  bears  at  the  crown  a  number  of  branches  2  to  5 
cm.  long,  having  a  small  pith  and  other  characters  of  a  rhizome. 
The  root  is  official. 

Lactuca  virosa  (Poison  lettuce)  is  a  biennial  prickly  herb, 
with  milky  latex  and  oblong-obovate,  spinose-toothed,  runcinate 
basal  leaves  and  with  alternate,  somewhat  sessile  or  auriculate, 
scattered  stem  leaves,  the  apex  and  margin  being  spinose.  The 
flowers  are  pale  yellow  and  occur  in  heads  forming  terminal  pani- 
cles. The  involucre  is  cylindrical  and  consists  of  several  series 
of  bracts.  The  flowers  are  all  ligulate  and  the  anthers  are  sagit- 
tate at  the  base.  The  achenes  are  flattish-oblong,  and  the  pappus, 
which  is  raised  on  a  stalk,  is  soft-capillary,  as  in  Taraxacum. 
The  prepared  milk-juice  is  official  as  Lactucarium. 

Eupatorium  perfoliatum  (Boneset  or  Common  thorough  wort). 
— The  leaves  and  flowers  are  used  in  medicine. 


CLASSIFICATION  OF  ANGIOSPERMS.  713 

Eupatorium  sebandianum,  which  is  added  to  Mate  as  a  sweet- 
ening agent,  contains  two  sweet  glucosides ;  eupatorin  and  reban- 
din ;  a  bitter  principle,  and  a  resin. 

GRINDELIA  species. — The  plants  are  perennial,  greenish-yellow, 
resinous  herbs,  sometimes  being  under-shrubs,  with  alternate> 
sessile  or  clasping,  oblong  to  lanceolate,  spinulose-dentate  leaves, 
and  large,  terminal,  yellowish  heads,  consisting  of  both  ligulate 
and  tubular  flowers.  The  leaves  and  flowering  tops  of  Grindelia 
cainporum,  G.  cuneifolia  and  G.  squarrosa  are  official. 

Erigeron  canadensis  or  Leptilon  caiiadense  (Canada  fleabane) 
is  an  annual  or  biennial,  hispid-pubescent  herb  found  growing 
in  fields  and  waste  places  in  nearly  all  parts  of  the  world.  The 
stems  are  simple,  with  numerous  crowded  leaves  and  numerous 
flowers  occurring  in  terminal  panicles.  The  plants  are  sometimes 
branched  and  i  to.  3  M.  high.  The  leaves  are  linear,  nearly  entire, 
of  a  pale  green  color,  the  lower  and  basal  ones  being  spatulate, 
petiolate  and  dentate  or  incised.  The  flowers  are  white  and  the 
heads  are  composed  of  both  ligulate  and  tubular  florets,  the  former 
being  pistillate  and  not  longer  than  the  diameter  of  the  disk.  The 
pappus  consists  of  numerous  capillary  bristles  and  the  involucre, 
which  is  campanulate,  consists  of  five  or  six  series  of  narrow, 
erect  bracts.  The  fresh  flowering  herb  contains  0.3  to  0.4  per  cent, 
of  a  volatile  oil  which  is  official,  tannin,  and  a  small  amount  of 
gallic  acid.  The  oil  is  obtained  by  distillation  and  consists  chiefly 
of  d-limonene. 

The  genus  Erigeron  includes  a  number  of  species  which  have 
medicinal  properties.  E.  annuus  (Sweet  scabious  or  Daisy  flea- 
bane)  is  a  low,  branching,  annual  herb,  characterized  by  its  linear- 
lanceolate  or  ovate-lanceolate  leaves  and  its  conspicuous  flowers, 
which  resemble  those  of  the  common  daisy,  the  ray-flowers  often 
being  tinged  with  purple  (Fig.  393).  It  contains  a  volatile,  oil 
resembling  that  of  Canada  fleabane,  and  tannin.  The  Philadel- 
phia fleabane  (Erigeron  philadelphicus)  is  a  perennial  herb  pro- 
ducing stolons,  and  has  clasping  or  cordate  leaves,  the  basal  being 
spatulate,  and  is  further  distinguished  by  its  light  purplish-red 
ray-flowers. 

Anthemis  nobilis  (Roman  chamomile)  is  an  annual  or  peren- 


714  A  TEXT-BOOK  OF  BOTANY. 

nial,  procumbent,  branched  herb,  with  numerous  2-  to  3-pinnately 
divided  leaves,  the  ultimate  segments  being  narrow-linear.  The 
flowers  occur  in  terminal  heads  with  long  peduncles,  a  conical 
torus  and  few  white  pistillate  ray-flowers.  The  flowers  of  culti- 


FIG.  393.    Daisy-fleabane  (Erigeron  annuus). 

vated  plants  are  official  (see  Vol.  II),  the  heads  consisting  mostly 
of  ligulate  flowers,  forming  so-called  "  double  flowers,"  as  in  the 
cultivated  chrysanthemums. 

Anacyclus  Pyrethrwn   (Pellitory)  is  a  perennial  herb  resem- 
bling Anthemis  nobilis  in  its  general  characters.    The  ray-flowers, 


CLASSIFICATION  OF  ANGIOSPERMS. 


715 


however,  are  white  or  purplish,  and  the  pappus  consists  of  a  ring 
or  scale.    The  root  is  official. 

Matricaria  Chamomilla  (German  chamomile)  is  an  annual, 
diffusely  branched  herb,  with  pinnately  divided  leaves,  consisting 
of  few,  linear  segments.  The  flowers  are  official  (Figs.  228, 
394). 


FIG.  394.     A  single  plant   of  Matricaria  Chamomilla,   showing  nnely   divided  leaves  and 
numerous   composite  flowers. — After   Newcomb. 

Arnica  montana  is  a  perennial  herb  with  small  rhizome; 
nearly  simple  stem ;  opposite,  somewhat  connate,  entire,  spatulate, 
hairy  leaves,  and  yellow  flowers  in  large  heads  with  long  peduncles. 
The  flowers  are  official. 

Arctium  Lappa  (Burdock)  is  a  coarse,  branched,  biennial  or 


7i6 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  395.  Chicory  or  Succory  (Cichorium  Intybus),  a  branching  perennial  herb  with 
oblong  or  lanceolate,  more  or  less  clasping  leaves  and  axillary  clusters  of  violet-blue  flowers. 
The  plant  is  cultivated  as  a  pot  herb  and  salad,  and  the  young  roots  are  used  like  carrots. 
The  plant  is  more  widely  grown  for  its  roots,  which  are  used  in  the  preparation  of  a  substi- 
tute of  coffee. — After  Brown. 


CLASSIFICATION  OF  ANGIOSPERMS. 


717 


perennial  herb,  with  alternate,  broadly  ovate,  repand,  entire,  tomen- 
tose,  mostly  cordate  leaves,  the  basal  ones  being  from  30  to  45  cm. 
long.  The  flowers  are  purplish-red  or  white,  tubular  and  form 
rather  large  corymbose  heads ;  the  involucre  consists  of  numerous 
lanceolate,  rigid,  nearly  glabrous  bracts,  which  are  tipped  with 


PIG.  396.  Burdock  (Arctium  Lap  pa),  a  biennial  herb  with  large,  mostly  cordate 
leaves  crowded  at  the  base  of  the  stems,  and  bearing  small  clusters  of  purplish  flowers  in 
the  shorter  branches  above.  It  is  a  common  roadside  weed,  and  well  known  because  of 
the  burr-like  fruits,  consisting  of  the  hooked  tips  of  the  bracts  of  the  involucre. — After 
Brown. 

hooked,  spreading  bristles.  The  achenes  are  oblong  and  some- 
what 3-angled,  and  the  pappus  consists  of  numerous  short  bristles 
(Fig.  396).  The  root  is  used  in  medicine. 

The  common  burdock  (Arctium  minus)  resembles  A.  Lap  pa, 
but  is  a  smaller  plant  and  is  more  common  in  the  United  States. 
The  heads  are  smaller  and  the  inner  bracts  are  shorter  than  the 


718  A  TEXT-BOOK  OF  BOTANY. 

tubular  flowers,  the  bristles  of  this  series  being  erect  and  with 
the  outer  spreading. 

Calendula  officinalis  (Marigold)  is  an  annual  herb  with  alter- 
nate, spatulate,  oblanceolate,  entire  or  serrate  leaves.  The  flowers 
are  yellow  and  form  solitary  heads,  consisting  of  both  ray  and 
tubular  florets.  In  the  cultivated  varieties  most  of  the  tubular 
florets  are  changed  to  ligulate,  the  latter  being  official  (Fig.  227). 

While  the  Compositae  include  a  large  number  of  genera  and 
species,  the  plants  do  not  yield  many  important  drugs,  although  a 
number  are  used  in  medicine  and  for  other  purposes. 

The  so-called  INSECT  FLOWERS  (Pyrethri  F lores)  are  the 
partly  expanded  flower-heads  of  several  species  of  Chrysanthe- 
mum, and  are  used  in  the  preparation  of  a  powder  which  is  a 
powerful  insecticide.  T.he  plants  are  perennial  herbs  resembling 
in  their  habits  the  common  white  daisy  (C.  Leucanthemum) .  The 
DALMATIAN  Insect  Flowers  are  obtained  from  C.  cineraria: folium, 
growing  in  Dalmatia,  and  cultivated  in  Northern  Africa,  Cali- 
fornia and  New  York.  The  heads  as  they  occur  in  the  market 
are  about  12  mm.  broad,  light  yellowish-brown  and  have  a  slightly 
rounded  or  conical  torus,  which  is  about  12  mm.  in  diameter  and 
consists  of  2  or  3  series  of  lanceolate  involucral  scales.  The  ray- 
florets  are  pistillate,  the  corolla  varying  in  length  from  i  to  2  cm. 
and  having  numerous  delicate  veins  and  3  short,  obtuse  or  rounded 
teeth.  The  tubular  flowers  are  perfect  and  about  6  mm.  long.  The 
ovary  is  5-ribbed  and  the  pappus  forms  a  short,  toothed  crown. 
The  odor  is  distinct  and  the  taste  bitter. 

PERSIAN  Insect  Flowers  are  derived  from  C.  rosemn  and  C. 
Marschallii,  growing  in  the  Caucasus  region,  Armenia  and  North- 
ern Persia.  The  heads  are  about  the  size  of  those  of  C,  cinerarice- 
folium;  the  torus  is  dark  brown;  the  involucral  scales  and  ray- 
florets  are  purplish-red ;  the  ovary  is  lo-ribbed. 

Insect  flowers  contain  from  a  trace  to  0.5  per  cent,  of  a  vola- 
tile oil,  the  Persian  flowers  containing  the  larger  proportion,  and 
the  amount  decreasing  with  the  maturing  of  the  flowers.  They 
also  contain  two  resins,  varying  from  4  to  7  per  cent.,  the  larger 
amount  being  found  in  the  Dalmatian  flowers ;  a  small  quantity 
of  a  glucO'side  and  a  volatile  acid. 

The  principle  toxic  to  insects  is  PYRETHRON,  an  amber-yellow, 


CLASSIFICATION  OF  ANGIOSPERMS.  719 

syrupy  substance  which  is  the  ester  of  certain  unidentified  acids, 
and  on  saponification  yields  the  alcohol  pyrethrol  which  crystal- 
lizes in  fine  needles.  The  acids  combined  in  the  ester  pyrethron 
do  not  give  crystalline  salts. 

WORMWOOD  or  Absinthium  consists  of  the  dried  leaves  and 
flowering  tops  of  Artemisia  Absinthium,  a  perennial,  somewhat 
woody,  branching  herb,  indigenous  to  Europe  and  Northern 
Africa,  cultivated  in  New  York,  Michigan,  Nebraska  and  Wis- 
consin and  naturalized  in  the  United  States  from  plants  that  have 
escaped  from  cultivation.  The  leaves  are  grayish-green,  gland- 
ular-hairy, I-  to  3-pinnately  divided,  the  segments  being  obovate, 
entire,  or  lobed ;  the  flowers  are  yellowish-green,  the  heads  being 
about  4  mm.  broad  and  occurring  in  raceme-like  panicles ;  the 
torus  is  hemispherical  and  the  involucre  consists  of  several  series 
of  linear  bracts,  the  inner  being  scale-like ;  the  florets  are  all 
tubular,  the  outer  ones  sometimes  being  neutral.  The  herb  is 
aromatic  and  very  bitter. 

The  fresh  drug  contains  about  0.5  per  cent,  of  a  VOLATILE  OIL 
which  is  of  a  dark  green  or  blue  color,  has  a  bitter,  persistent  taste 
but  not  the  pleasant  odor  of  the  plant,  and  consists  of  d-thujone 
(absinthol),  thujyl  alcohol  free  and  combined  with  acetic,  iso- 
valerianic  and  palmitic  acids,  phellandrene  and  cadinene.  The 
other  constituents  oi  the  drug  include  a  bitter  glucosidal  principle, 
ABSINTHIIN,  which  forms  white  prisms  and  yields  on  hydrolysis 
a  volatile  oil ;  a  resin ;  starch ;  tannin ;  succinic  acid,  potassium 
succinate,  and  about  7  per  cent,  of  ash.  The  plant  is  used  in  the 
preparation  of  the  French  liquor  known  as  ABSINTHE. 

Artemisia  Cina  yields  the  official  Santonin. 

Other  species  of  Absinthium  also  yield  volatile  oils,  as  the 
COMMON  MUGWORT  (Artemisia  vulgaris),  which  yields  from  o.i 
to  0.2  per  cent,  of  an  oil  containing  cineol ;  Artemisia  Barrelieri, 
which  contains  an  oil  consisting  almost  entirely  of  thujone,  and 
said  to  be  used  in  the  preparation  of  Algerian  absinthe. 

SAFFLOWER  consists  of  the  dried  florets  of  Carthamus  tinc- 
torius,  an  annual  herb  which  is  known  only  in  cultivation.  The 
florets  are  tubular,  yellowish-red,  the  corolla  tube  being  about 
2  cm.  long  and  with  5  small,  linear  lobes  ;  the  stamens  are  exserted. 
The  ovary  with  the  long,  slender  style  is  usually  not  present  in 


720  A  TEXT-BOOK  OF  BOTANY. 

the  drug  (Fig.  227,  C).  Safflower  contains  a  small  percentage 
of  a  yellow  coloring  principle  (safflower-yellow),  which  is  soluble 
in  v/ater,  and  0.3  to  0.6  per  cent,  of  a  red  coloring  principle  (car- 
thamin  or  carthamic  acid),  which  is  insoluble  in  water  but  soluble 
in  alcohol,  the  solution  having  a  purplish-red  color.  A  volatile 
oil  is  also  present.  Carthamin  is  used  in  conjunction  with  French 
chalk  in  the  preparation  of  a  rouge. 

TANSY  is  the  dried  leaves  and  tops  of  Chrysanthemum  (Tana- 
cetum  vulgar  e),  a  perennial,  aromatic  herb  indigenous  to  Europe, 
extensively  cultivated  and  naturalized  in  the  United  States.  The 
leaves  are  large  and  pinnately  divided,  and  the  flowers,  both  tubu- 
lar and  ligulate,  are  yellow,  the  heads  being  in  terminal  corymbs. 

The  plant  yields  from  o.i  to  0.3  per  cent,  of  a  volatile  oil, 
consisting  of  thujone,  borneol  and  camphor ;  and  3  resins. 

ELECAMPANE  (Inula  Helenium)  is  a  large,  perennial,  densely 
pubescent  herb  with  alternate  leaves  and  large,  solitary  terminal 
heads,  consisting  of  yellow  tubular  and  ligulate  florets  (Fig.  227). 
The  plant  is  indigenous  to  Central  Europe  and  Asia,  and  natural- 
ized in  North  America  from  Canada  to  North  Carolina.  The 
root  is  used  in  medicine  and  was  formerly  official  as  INULA. 

The  root  of  Polymnia  Uvedalia,  a  plant  closely  related  to 
Inula,  but  indigenous  to  the  United  States  east  of  the  Mississippi, 
contains  a  volatile  oil,  a  glucoside,  tannin,  and  a  resinous  sub- 
stance consisting  of  two  resins,  one  of  which  is  pale  yellow  and 
soft,  the  other  dark  brown  and  hard. 

The  following  Composite,  while  not  of  very  great  importance, 
are  used  in  some  localities: 

YARROW  (Achillea  Mille folium)  is  a  common  weed  naturalized 
from  Europe  (Fig.  397),  and  contains  about  o.i  per  cent,  of  a  dark 
blue  volatile  oil  with  a  strongly  aromatic  odor  and  a  small  amount 
of  a  bitter  alkaloid,  achilleine.  The  roots  of  yarrow,  on  the  other 
hand,  yield  a  volatile  oil  with  a  valerian-like  odor.  Achillea  nobilis 
of  Europe  contains  an  oil  resembling  that  of  yarrow,  but  it  is  of 
finer  quality  and  has  a  spice-like  taste.  Achillea  moschata,  an 
alpine  plant  of  Europe,  yields  three  alkaloids  and  a  volatile  oil 
containing  cineol,  and  is  used  in  Italy  in  the  preparation  of  the 
liquor,  "Esprit  d'  Iva."  Achillea  tanacetifolia  yields  a  blue  volatile 
oil  having  the  odor  of  tansy. 


CLASSIFICATION  OF  ANGIOSPERMS.  721 


FIG.  397.  Yarrow  or  Milfoil  (Achillea  Millefolium),  a  perennial  herb,  branching  only 
at  the  top  and  bearing  deeply  pinnatifid  leaves,  the  segments  being  very  narrow.  The 
flowers  are  small,  white,  occasionally  crimson  and  arranged  in  large,  terminal  corymbs. — 
Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture. 

The  HIGH  GOLDEN-ROD  (Solidago  canadensis)  yields  0.63  per 
cent,  of  a  volatile  oil,  consisting  chiefly  of  pinene,  with  some  phel- 
46 


722 


A  TEXT-BOOK  OF  BOTANY. 


landrene  and  dipentene,  and  containing  about  9  per  cent,  of 
borneol,  3  per  cent,  of  bornyl  acetate  and  some  cadinene.  The 
True  or  ANISE-SCENTED  GOLDEN-ROD  (Solidago  odora)  yields 
an  aromatic  volatile  oil  and  a  small  amount  of  tannin. 


FIG.  398.  Method  of  gathering  the  pollen  of  Golden-rod  (Solidago  Shortii}  for  immuniz- 
ing the  hay-fever  horses.  The  plant  is  gathered  just  about  the  time  that  the  pollen-sacs 
are  ready  to  open,  then  taken  to  a  sunny  room — free  from  draft  and  air  disturbances — 
placed  slanting  in  a  basin  filled  with  water,  the  blossoms  drooping  over  the  sides  of  the 
vessel,  with  clean,  smooth  paper  spread  underneath  them.  The  following  morning  the 
pollen  will  be  on  the  paper  and  can  readily  be  gathered  with  a  feather-top  or  a  quill. — 
After  Schimmel  &  Co. 

The  rhizome  of  the  large  Button-snakeroot  (Lacinaria  scari- 
osa),  growing  in  the  eastern  and  central  portion  of  the  United 
States  and  Canada,  contains  o.i  per  cent,  of  volatile  oil,  about 
5  per  cent,  of  resin,  and  2  per  cent,  of  a  caoutchouc-like  substance. 


CLASSIFICATION  OF  ANGIOSPERMS.  723 

COLTSFOOT  (Tussilago  Farfara)  is  a  plant  indigenous  to 
Europe  and  naturalized  in  the  Northern  United  States  and  Can- 
ada. It  is  an  acaulescent  herb  with  a  slender  rhizome  30  to  40 
cm.  long ;  nearly  orbicular,  somewhat  lobed  and  tomentose  leaves, 
and  large,  solitary,  yellow  flowers  appearing  before  the  leaves. 
The  plant  contains  an  acrid  volatile  oil,  a  bitter  glucoside,  resin 
and  tannin. 

ECHINACEA  is  the  root  of  Brauneria  (Rudbeckia)  pur  pur  ea, 
a  plant  growing  in  rich  soil  from  Virginia  to  Illinois  and  south- 
ward, and  of  B.  angustifolia,  growing  from  the  Northwest  Terri- 
tory to  Texas  (Fig.  399).  The  drug  contains  an  alkaloid  and 
0.5  to  i  per  cent,  of  an  acrid  resinous  substance  to  which  the 
medical  properties  are  due. 

ROSIN  WEED  or  COMPASS  PLANT  (Silphium  laciniatum) , 
found  growing  from  Ohio  to  South  Dakota  and  south  to  Texas, 
produces  an  oleo-resin  which  exudes  either  spontaneously  or  from 
the  punctures  of  insects,  and  contains  about  19  per  cent,  of  vola- 
tile oil,  and  37  per  cent,  of  acid  resin. 

The  THISTLE  (Cnicus  benedictus)  contains  a  crystalline  bitter 
principle,  cnicin,  which  is  colored  red  with  sulphuric  acid. 

The  Mexican  drug  PIPITZAHOAC  is  the  rhizome  of  Perezia 
Wrightii,  P.  nana  and  P.  adnata,  plants  found  in  Southwestern 
Texas  and  Mexico*.  It  contains  about  3.6  per  cent,  of  a  golden- 
yellow  crystalline  principle,  pipitzahoic  acid,  which  appears  to  be 
related  to  oxythymoquinone  and  is  colored  an  intense  purple  with 
alkalies  and  alkaline  earths. 

LION'S  FOOT,  the  root  of  Prenanthes  Serpentaria,  P.  alba  and 
other  species  of  Nabalus  growing  in  the  United  States,  contains 
bitter  principles,  resin  and  tannin.  Mio  Mio  (Baccharis  cordi- 
folia),  of  South  America,  is  poisonous  to  sheep  and  cattle  and 
contains  an  alkaloid,  baccharine,  and  a  bitter  principle.  SPINY 
CLOTBUR  (Xanthium  spinosum)  contains  a  bitter  resin  and  possi- 
bly a  volatile  alkaloid.  The  fruit  of  Xanthium  spinosum,  a 
common  weed  naturalized  from  Europe,  contains  an  amorphous, 
non-glucosidal  substance,  xanthostrumarin,  which  forms  precip- 
itates with  a  number  of  the  alkaloidal  reagents.  SNEEZE- WEED 
(Helenium  autumnale)  contains  a  volatile  oil,  a  bitter  glucoside 
and  tannin.  Helenium  tenuifolium,  of  the  Southern  United  States, 


724 


A  TEXT-BOOK  OF  BOTANY. 


FIG.  399.  A  flowering  specimen  of  the  Purple  Cone-flower  (Brauneria  angustifolia) , 
showing  the  3-nerved  lanceolate  leaves  and  2  of  the  flower  heads  with  the  characteristic 
long  spreading  rays. — After  Newcomb. 

is  a  narcotic  poison.  PARA  CRESS  (Spilanthes  oleracea),  of  trop- 
ical America,  contains  a  soft  pungent  resin  and  a  crystallizable 
principle,  spilanthin.  The  common  white  daisy  (Chrysanthemum 


CLASSIFICATION  OF  ANGIOSPERMS.  725 

Leucanthemum)  yields  about  0.15  per  cent,  of  a  greenish  volatile 
oil  with  the  odor  of  chamomile  and  mint. 

CHICORY,  the  root  of  Cichorium  Intybus,  a  perennial  herb 
with  blue  or  purplish  ligulate  florets,  indigenous  to  and  cultivated  in 
Europe  and  naturalized  in  the  United  States  (Fig.  395),  is  used 
in  medicine  as  well  as  in  the  preparation  of  a  coffee  substitute. 
The  root  is  spindle-shaped,  somewhat  resembling  Taraxacum,  but 
is  of  a  light  brown  color  and  the  laticiferous  vessels  are  arranged 
in  radial  rows  in  the  somewhat  thinner  bark.  It  contains  a  bitter 
principle  and  a  large  amount  of  inulin.  In  the  preparation  of  a 
coffee  substitute  the  root  is  cut  into  rather  large,  equal  pieces  and 
roasted,  after  which  it  is  ground  to  a  yellowish-brown,  coarse 
powder.  The  grains  are  heavier  than  water,  imparting  to  it  a 
yellowish-brown  color.  Under  the  microscope  it  is  distinguished 
by  the  branching  latex-tubes  and  rather  short,  oblique  tracheae 
with  rather  large,  simple  pores. 

The  SUNFLOWER  (Helianthus  annuus)  is  an  annual  herb  indig- 
enous to  tropical  America  and  extensively  cultivated.  The  plant 
is  grown  on  a  large  scale  in  Russia,  Hungary,  Italy  and  India  for 
its  fruits,  which  yield  a  fixed  oil  resembling  that  of  cotton  seed. 
The  achenes  (so-called  seeds)  are  obovate,  flattened,  externally 
black  or  with  alternate  white  and  black  stripes,  the  pappus  con- 
sisting of  two  deciduous,  chaffy  scales.  Sunflower  seed-cake  is 
readily  distinguished  by  a  few  of  the  fragments  of  the  epicarp, 
with  the  characteristic  twin,  unicellular,  non-glandular  hairs  and 
large,  oblique,  but  rather  short,  sclerenchymatous  fibers.  Besides 
40  per  cent,  of  a  fixed  oil,  the  seeds  contain  a  peculiar  glucosidal 
tannin,  helianthic  acid,  which  is  colored  deep  green  with  ferric 
chloride  and  yellow  with  alkalies.  The  root  contains  inulin ;  the 
shoot  asparagin,  and  the  fresh  pith  about  1.5  per  cent,  of  potas- 
sium nitrate.  The  pith  has  been  used  in  the  preparation  of 
MOXA,  a  combustible  vegetable  material  which  burns  without  fus- 
ing and  is  used  by  the  Portuguese  to  destroy  any  deep-seated 
inflammation.  The  pith  of  various  species  of  Artemisia,  which 
also  contains  considerable  potassium  nitrate,  furnishes  the  Chinese 
Moxa. 

JERUSALEM  ARTICHOKE  (Helianthus  tuber osus)  is  a  large, 
coarse,  pubescent  herb  with  yellow  ray-florets,  which  is  indigenous 


726  A  TEXT-BOOK  OF  BOTANY. 

to  the  Middle  United  States  and  sometimes  cultivated.  The 
tubers,  which  resemble  artichokes,  are  more  or  less  elongated  or 
pear-shaped,  reddish-brown,  somewhat  annulate,  and  internally 
white  or  reddish.  They  have  been  used  as  a  substitute  for  pota- 
toes and  contain  about  16  per  cent,  of  the  following  carbohydrates : 
Inulin,  pseudo-inulin,  inulenin,  saccharose,  helianthenin,  and  syn- 
antherin.  In  early  spring  with  the  development  of  the  tubers  there 
is  formed  a  small  quantity  of  dextrose  and  levulose. 

The  Globe  artichoke  of  the  gardens  (Cynara  Scolymus)  is  a 
hardy  perennial  and  is  valued  on  account  of  the  fleshy  involucral 
scales  and  torus,  which  are  edible. 

The  POLLEN  of  a  number  of  plants  of  the  Composite,  as  rag- 
weed (Ambrosia),  golden-rod  (Solidago),  aster  and  chrysanthe- 
mum, is  said  to  be  responsible  for  the  autumnal  cold,  known  as 
HAY  FEVER.  A  similar  disease  is  produced  in  spring  and  early 
summer  by  the  pollen  of  certain  grasses.  It  has  been  found  that 
the  pollen  grains  of  these  plants  contain  a  highly  toxic  substance, 
belonging  to  the  toxalbumins,  which  is  the  cause  of  the  disease. 
By  inoculation  of  rabbits,  goats  and  horses  with  this  toxalbumin 
a  serum  containing  an  antitoxin  is  obtained  which  neutralizes  the 
pollen  toxin  and  protects  those  who  are  susceptible  to  hay  fever 
from  its  attacks.  In  practice  the  serum  is  prepared  by  injecting 
the  toxalbumin  subcutaneously  into  horses,  the  serum  being  known 
in  commerce  as  POLLANTIN  (Fig.  398). 

The  pollen  of  the  following  plants  is  toxic:  aster,  barley, 
chrysanthemum,  convallaria,  corn-flower,  golden-rod,  grasses, 
honeysuckle,  oats,  cenothera,  ragweed,  rice,  rye,  spinach,  wheat, 
and  zea.  The  constituents  of  rye  pollen  are  86.4  per  cent,  of 
organic  matter,  10.2  of  water,  and  3.4  of  ash.  The  organic  matter 
consists  of  40. per  cent,  of  toxic  substances,  3  of  fixed  oil,  25  of 
carbohydrates,  and  18  of  a  non-albuminous  substance.  The  num- 
ber of  pollen  grains  per  gram  varies  in  different  plants :  from 
Indian  corn  being  7,000,000,  of  rye  20,000,000,  of  golden-rod 
80,000,000,  and  of  ragweed  90,000,000. 

The  flowers  of  the  Japanese  chrysanthemum  "  Riuno-kiku  " 
(Chrysanthemum  sinense  japonicum)  yield  0.8  per  cent,  of  a 
volatile  oil  containing  an  optically  inactive  crystalline  iso-camphor. 


CHAPTER  VI. 
CULTIVATION  OF  MEDICINAL  PLANTS. 

WHEN  the  forests  and  woods  were  full  of  wild  medicinal  plants 
that  could  be  easily  gathered,  there  was  hardly  an  incentive 
to  consider  the  farming  of  them.  Now  that  they  are  becoming 
scarcer,  the  need  is  especially  apparent.  Our  interest  in  the  culti- 
vation of  medicinal  plants,  however,  is  not  primarily  because  there 
is  a  growing  scarcity  of  the  sources  of  supply,  but  in  order  that 
drugs  of  uniform  quality  and  increased  value  may  be  had.  For- 
tunately, there  is  a  tendency  on  the  part  of  some  manufacturing 
pharmacists  to  concentrate  their  efforts  upon  a  few  plants  yielding 
drugs  and  to  study  them  in  relation  to  their  active  principles 
throughout  different  periods  of  the  season.  In  addition  to  these 
actual  experiments,  there  are  numerous  inquiries  made  regarding 
the  possibilities  of  the  successful  farming  of  medicinal  plants. 
These  inquiries  come  from  various  people  who,  for  one  reason 
or  other,  would  like  to  get  into  country  life  and  have  some  definite 
work  to  do.  Many  of  them  have  never  had  any  practical  experi- 
ence in  growing  plants  other  than  taking  care  of  a  garden  plot. 
Nearly  all  know  nothing  of  the  commerce  of  drugs  and  have  no 
idea  of  the  problems  connected  with  the  disposition  and  marketing 
of  them.  Fortunately,  some  experiments  have  been  conducted 
and  there  is  some  general  information  as  to  how  one  should 
proceed  in  the  work.  However,  it  must  be  said  at  the  outset,  no 
one  can  grow  medicinal  plants  without  having  some  training  and 
special  education  for  it ;  and  unless  one  is  familiar  with  the  prac- 
tical conditions  of  trade,  that  is  in  regard  to  the  markets  and 
prices  paid  for  drugs,  even  though  successful  in  raising  a  good 
crop,  one  may  not  be  able  to  dispose  of  it.  It  is  very  difficult  to 
lay  down  any  one  rule  that  can  be  invariably  followed  on  this  sub- 
ject. In  fact,  very  little  work  has  been  done  to  enable  us  to  draw 
other  than  very  broad  conclusions.  The  first  thing  to  be  consid- 
ered is  locality.  Of  course,  tropical  plants  would  not  grow  in 
the  temperate  zone,  nor  mountainous  plants  at  the  seaside,  although 
even  here  there  are  exceptions  that  only  experiments  can  show. 

727 


728  A  TEXT-BOOK  OF  BOTANY. 

Then  again,  there  are  plants  which  grow  only  in  the  rich  woodland 
soil,  while  others  grow  in  barren  soil  in  open  places.  Some  plants 
require  special  kinds  of  soil,  as  Atropa  Belladonna  and  Cannabis 
sativa,  which  do  not  seem  to  reach  a  high  state  of  cultivation  except 
in  a  calcareous  soil.  On  the  other  hand,  the  plants  of  the  Ericaceae 
are  peculiar  in  that  they  require  an  acid  soil  (pp.  250,  656). 

In  beginning  this  work  in  a  new  locality  it  is  very  important 
to  make  a  rather  careful  survey  of  the  plants  growing  wild,  or 
those  which  have  become  naturalized.  It  would  be  safe  to  say 
that  within  certain  limits,  if  there  are  a  number  of  genera  of  any 
family  well  represented  that  has  some  of  the  habits  of  the  plant 
with  which  one  desires  to  experiment  with,  there  is  a  probability 
that  it  may  be  grown  successfully.  This  can  be  ascertained  to  some 
extent  by  the  nature  of  the  plants  that  are  brought  under  cultiva- 
tion. For  instance,  digitalis  might  be  grown  very  successfully 
in  localities  where  it  is  cultivated  and  has  become  naturalized. 
By  a  priori  reasoning,  in  the  cultivation  of  licorice,  the  ideal 
location  for  growing  the  plant  would  be  in  the  West  and  North- 
west where  the  wild  licorice,  Glycyrrhiza  lepidota,  is  indigenous. 
In  addition,  it  is  necessary  to  study  the  best  ways  of  propagating 
the  plant  one  wishes  to  grow.  Sometimes  this  is  by  means  of 
seeds,  as  in  belladonna  and  digitalis ;  at  other  times  it  is  by  propa- 
gation of  rhizomes,  as  hydrastis  and  glycyrrhiza ;  or  again  by 
root-stocks  or  prostrate  stems,  as  in  the  mints.  Sometimes  both 
seeds  and  cuttings  may  be  used,  as  in  the  case  of  hydrastis. 

PLANTS  GROWN  FROM  SEEDS. — A  large  number  of  plants  can  be 
grown  from  seeds,  and  when  they  are  grown  in  this  manner,  espe- 
cially in  a  temperate  climate,  where  the  growing  season  is  rather 
short,  it  is  necessary  to  begin  the  germination  of  the  seed  early 
in  the  spring.  This  must  be  done  in  the  house  or  under  conditions 
where  there  is  some  protection.  They  may  be  sown  either  in  small 
boxes  or  seed  pans,  in  which  the  soil  is  quite  sandy  or  made  up 
largely  of  broken  granitic  rock  (Fig.  400),  and  which  must  be 
clean  and  free  from  organic  matter  that  is  likely  to  mould.  The 
seeds  should  not  be  planted  too  deep,  and  the  boxes  or  pans  should 
be  covered  with  glass  so  as  to  condense  or  hold  moisture.  Of 
course,  where  there  is  the  necessary  attention,  so  far  as  keeping 
the  earth  moist  is  concerned,  this  can  be  dispensed  with.  The 


CULTIVATION  OF  MEDICINAL  PLANTS.        729 


FlG.  400.  Digitalis  Seedlings  in  seed  pans,  ready  to  be  transplanted  into  plant  flats. 
This  is  the  first  step  in  the  propagation  of  Digitalis.— From  the  Experimental  Farm  of 
Eli  Lilly  &  Company,  Indianapolis,  Ind. 


730 


A  TEXT-BOOK  OF  BOTANY. 


time  required  in  germination  will  vary  considerably.  Many  seeds 
will  germinate  well  within  two  weeks ;  usually  probably  four  or 
five  weeks  are  necessary.  Occasionally  some  seeds,  as  with  roses, 
may  require  a  year  or  two.  The  present  tendency  is  to  shorten 
the  period  of  germination  in  several  ways.  The  simplest,  possibly, 
is  to  place  the  seeds  in  water  for  24  hours.  If  the  seed-coat  is 
more  or  less  lignified  and  non-porous,  boiling  water  is  poured  upon 
them,  or  some  special  treatment  may  be  given,  as  the  use  of  dilute 


FIG.  401.  Digitalis  Seedlings  in  plant  flat,  three  months  after  transplanting  from 
seed  pans.  These  plants  are  now  ready  to  be  transferred  to  cold  frames. — From  the  Ex- 
perimental Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

or  even  concentrated  mineral  acids.  For  instance,  in  the  culti- 
vation of  Paraguay  tea  or  mate,  for  many  years  it  was  found  that 
the  seeds  would  not  germinate  unless  they  had  previously  passed 
through  the  alimentary  tract  of  certain  birds.  Later  it  was  found 
that  the  same  results  could  be  obtained  by  placing  the  seeds  in  solu- 
tions of  hydrochloric  acid.  Miller  reports  that  he  has  obtained 
good  results  in  the  case  of  belladonna  by  first  placing  the  seeds  for 
30  or  40  seconds  in  concentrated  sulphuric  acid.  The  germination 
of  seeds  may  also  be  hastened  by  certain  mechanical  means.  These 
are  employed  when  the  seed-coat  is  unusually  thick  and  not  easily 


CULTIVATION  OF  MEDICINAL  PLANTS.        731 

penetrated  by  the  moisture;  or  if  the  seeds  are  large,  they  may 
be  filed  in  one  or  two  places;  when  they  are  small  they  may  be 
shaken  with  sharp,  angular  sand  until  the  exterior  is  somewhat 
roughened. 

After  the  seedlings  have  put  forth  a  few  leaves  they  are  then 
set  out  in  suitable  boxes  known  as  flats  (Fig.  401)  which  contain 
a  soil  having  a  fair  amount  of  nutriment.  The  plants  must  be 
watched  at  this  point  to  see  that  there  is  no  damping  off  and  loss 
by  reason  of  attacks  by  soil  micro-organisms. 


FIG.  402.  Cold  frames  for  use  in  propagating  such  plants  as  Digitalis,  Belladonna, 
Henbane,  etc.  The  young  seedling  plants  are  transferred  from  the  greenhouse  to  these 
cold  frames  in  late  spring  for  the  purpose  of  hardening  them  before  transplanting  to  the 
open  field. — From  the  Experimental  Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

Should  there  be  a  damping  off  and  loss  of  seedlings  some 
method  should  be  employed  to  overcome  it.  Recently  the  De- 
partment of  Agriculture  has  utilized  dilute  sulphuric  acid,  which 
Kraemer  has  shown  is  the  active  principle  produced  whenever 
sulphur  is  used  in  the  greenhouse,  for  the  destruction  of  insect 
pests,  as  well  as  the  blights  due  to  fungi  and  other  micro- 
organisms. 

The  plants  are  allowed  to  grow  in  the  flats  until  they  have 
developed  a  good  root  system  and  have  produced  a  shoot  with 
3  or  4  leaves.  They  are  then  transferred  to  cold  frames  (Fig. 
402),  where  they  remain  until  they  are  acclimatized  or  hardened 


732 


A  TEXT-BOOK  OF  BOTANY. 


sufficiently  to  be  planted  directly  in  the  soil.  This  transferring 
should  be  done  not  later  than  the  early  part  of  May.  The  structure 
and  use  of  the  cold  frame  is  perfectly  familiar  to  the  practical 
gardener. 

Sometimes  the  individual  plants  are  removed  from  the  flats 
and  placed  directly  in  the  soil  of  cold  frames.  .This  may  give 
them  a  temporary  setback,  as  the  roots  are  more  o-r  less  disturbed 


FlG.  403.     A  general  view  of  the  testing  and  breeding  of  medicinal  plants  at  the  Experi- 
mental Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

by  the  operation,  but  if  the  experiment  in  the  cold  frames  is  to  be 
continued  considerable  time  will  be  saved. 

If  the  plants  are  to  be  transplanted  out  of  doors  it  is  desirable 
that  this  should  be  done  as  soon  as  possible  after  the  last  days 
are  over  for  the  possibility  of  frost.  The  plants  are  arranged 
in  rows  and  set  sufficiently  far  apart  so  the  maximum  crop  per  acre 
can  be  obtained  (Figs.  403-407),  and  also  that  weeds  may  be 
pulled  out  and  the  ground  worked  over. 

The  above  outline  given  may  be  used  for  the  propagation  of 


CULTIVATION  OF  MEDICINAL  PLANTS.        733 

most  plants  by  seedlings.  Some  plants  are  rather  easily  grown  if 
care  is  taken  with  their  culture,  as  digitalis  and  belladonna.  Other 
plants,  like  hyoscyamus,  are  with  some  difficulty  cultivated,  and 
very  few  persons,  even  seedsmen,  are  uniformly  successful  in 
growing  aconite.  It  should  also  be  stated  that  there  are  a  number 
of  plants  yielding  medicinal  products  which  are  grown  from 
seeds  and  require  no  more  care  than  the  usual  garden  plants. 
Among  these  are  calendula,  Chrysanthemum  roscum,  echinacea, 


FlG.  404.     Harvesting   a  unit   test   plot   of  first-year   Digitalis. — From   the   Experimental 
Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

and  a  number  of  others  grouped  under  sweet,  pot,  and  medicinal 
herbs. 

PROPAGATION  BY  CUTTING. — This  is  a  common  method  of 
propagating  plants,  being  extensively  employed  by  florists.  A 
cutting  is  a  severed  portion  of  a  stem  having  one  or  more  nodes 
or  buds.  They  •  are  derived  either  from  over-ground  shoots, 
as  in  carnation,  rose,  geranium,  and  coleus,  or,  where  the  plant 
produces  root-stocks  or  rhizomes,  they  are  made  from  these  rather 
than  from  the  over-ground  shoots.  Not  all  plants  can  be  propa- 
gated equally  well  from  cuttings.  Some  plants  are  readily  propa- 


734 


A  TEXT-BOOK  OF  BOTANY. 


gated  in  this  way,  as  the  willows,  the  twigs  of  which,  when  they 
fall  off  or  are  broken  off,  frequently  take  root  in  the  moist  soil. 
Other  plants,  like  the  oak,  are  very  difficult  to  grow  from  cuttings. 
In  propagating  plants  from  rhizomes  the  latter  are  cut  into  pieces, 
each  of  which  has  one  or  two>  buds,  and  these  pieces  are  planted. 
Among  the  medicinal  plants  which  have  been  grown  from  cuttings 
of  rhizomes  are  licorice,  peppermint,  hydrastis,  and  ginger,  but 
it  is  likely  that  all  plants  which  produce  rhizomes  can  be  readily 


FIG.  405.     Goldenseal    (Hydrastis   canadensis)    farming   in    a    natural    woodland   glade. — 
From  Wellcome  Materia  Medica  Farm  near  Dartford,  England. 

propagated  in  this  manner.  Cuttings  of  over-ground  stems  are 
made  from  the  growing  parts  of  branches,  and  it  is  necessary  to 
have  them  of  such  a  length  that  at  least  one  node  may  be  placed 
in  the  soil.  These  are  at  first  planted  in  micaceous  soil  or  river 
sand,  which  should  be  kept  well  moistened.  It  is  desirable  that 
the  leaves  be  as  few  as  possible,  so  as  to  reduce  the  transpiring 
surface  until  the  young  roots  have  been  formed,  wrhich  may  take 
several  weeks  or  several  months.  Usually  the  lower  leaves  should 
be  cut  off  entirely,  while  the  others  may  be  partially  trimmed.  The 


CULTIVATION  OF  MEDICINAL  PLANTS.        735 

cuttings  should  also  be  protected  from  strong  light,  as  this  tends 
to  increase  transpiration,  and  also-  guarded  against  a  dry  atmos- 
phere, which  may  be  accomplished  by  covering  them  with  glass, 
particularly  during  the  day,  when  the  weather  is  dry.  Cuttings 
of  hard  wood  plants  intended  for  outdoor  culture  should  be  made 
in  the  fall.  They  should  be  6  or  8  inches  in  length,  kept  covered 
with  sand  in  a  suitable  place  during  the  winter,  and  planted  in  the 
spring. 


FIG.  406.      Goldenseal    (Hydrastis   canadensis)    farming   under   an   artificially   constructed 
shade. — From  Wellcome  Matena  Medica  Farm  near  Dartford,  England. 

In  the  case  of  both  ginseng  and  hydrastis,  one-year-old  plants 
are  often  supplied  by  growers,  and,  though  this  is  not  always  desir- 
able, yet  there  are  conditions  where,  for  experimental  purposes, 
they  may  be  used.  It  should  be  emphasized  that  it  is  not  merely  a 
matter  of  getting  rhizomes  or  young  plants,  but  a  very  careful 
study  should  be  made  of  the  conditions  governing  soil  and  light, 
and  which  favor  the  maximum  returns  from  the  crop  (Figs.  405- 
407).  Caution  should  be  exercised  in  the  use  of  manure  for  in- 
creasing the  yield  of  the  crop  as  well  as  the  plant  constituents. 


736 


A  TEXT-BOOK  OF  BOTANY. 


CULTIVATION  OF  MEDICINAL  PLANTS.        737 

The  method  for  producing  new  varieties  is  by  hybridization, 
or  cross-pollination,  of  different  related  species  or  varieties  (Fig. 
403).  The  offspring  is  known  as  a  HYBRID,  and  has  a  blending  of 
the  qualities  or  characters  of  the  two  parent  plants.  This  method 
is  mostly  employed  by  florists  who  desire  to  produce  some  new 
or  striking  flower,  or  by  horticulturists  who  desire  to  establish 
some  new  quality  or  transfer  a  desirable  quality  from  a  foreign 
plant  to  one  which  is  adapted  to  a  given  locality.  The  method 
has  not  been  largely  employed  in  the  cultivation  of  medicinal 
plants,  except  in  the  case  of  cinchona,  where  it  is  claimed  that  the 
barks  richest  in  alkaloids  are  the  direct  result  of  hybridization 
and  selection.  By  transplanting  and  special  methods  of  treat- 
ment, as  that  of  mossing,  the  alkaloidal  percentage  has  been  in- 
creased from  S  per  cent,  to  10,  whereas  by  hybridization  the 
amount  of  total  alkaloids  has  reached  as  high  as  16  per  cent.,  about 
three- fourths  being  quinine. 

COLLECTING  AND  DRYING  OF  DRUGS. — The  time  of  the  COLLEC- 
TION of  vegetable  drugs  is  of  prime  importance,  and,  while  it 
may  not  be  possible  to  make  extended  generalizations,  still,  the  fol- 
lowing rules  for  the  collection  of  various  drugs  may  be  given : 

(1)  Roots,  rhizomes,  and  barks  should  be  collected  immedi- 
ately  before   the  vegetative   processes   begin   in   the   spring,   or 
immediately  after  these  processes  cease,  which  is  usually  in  the 
fall. 

(2)  Leaves  should  be  collected  when  photosynthetic  processes 
are  most  active,  which  is  usually  about  the  time  of  the  develop- 
ment of  the  flowers  and  before  the  maturing  of  fruit  and  seed. 

(3)  Flowers  should  be  collected  prior  to  or  just  about  the 
time  of  pollination. 

(4)  Fruits  should  be  collected  near  the  ripening  period,  i.e., 
full  grown  but  unripe. 

(5)  Seeds  should  be  collected  when  fully  matured. 

It  should  be  emphasized  that  these  are  very  general  rules  for 
the  guidance  of  the  collector,  and  that  when  one  is  farming  drug 
plants  this  question  becomes  exceedingly  vital,  as  not  only  do  the 
constituents  vary  at  different  times  during  the  season,  but  there 
is  considerable  variation  in  the  amount  of  drug  obtained.  The 
exact  information  regarding  the  proper  time  of  gathering  any 
47 


738  A  TEXT-BOOK  OF  BOTANY. 

specific  drug  can  be  obtained  only  by  collecting  it  at  different 
times  during  the  season,  assaying  it  and  making  preparations 
from  it.  Experiments  thus  far  seem  to  show  that  belladonna 
leaves  collected  in  July  and  August  show  a  higher  toxicity  than 
those  gathered  in  September  or  October.  It  is  quite  possible  that 
after  the  removal  of  the  leaves  high  in  alkaloidal  content  in  July, 
another  crop  can  be  obtained  by  October.  It  is  important  to  bear 
in  mind  with  some  drugs  that  a  very  slight  difference  in  time  of 
gathering  and  manner  of  drying,  great  variation  of  the  active  con- 
stituents may  be  found,  as  with  many  of  the  Composite  flowers. 
It  is  only  when  they  are  in  the  bud  condition,  as  in  the  case  of 
insect  flowers,  and  santonica,  that  they  show  the  highest  amount 
of  active  principle.  Again,  depending  on  whether  an  article  is 
gathered  to  be  put  upon  the  market  or  whether  the  active  prin- 
ciples are  to  be  isolated,  as  in  the  manufacture  of  the  essential 
oils,  different  methods  are  followed,  depending  upon  the  nature  of 
the  plant  and  what  previous  experiments  have  demonstrated 
should  be  followed.  For  instance,  while  in  the  preparation  of  oil 
of  peppermint  the  herb  is  first  dried,  yet  in  other  cases  the  col- 
lected material  must  be  previously  macerated  in  order  to  obtain 
the  largest  yield  of  oil,  as  with  those  plants  yielding  volatile  oils 
containing  either  cyano-benzaldehyde  or  methyl-salicylate. 

Too  much  attention  cannot  be  given  to  the  entire  question 
of  the  harvesting  of  the  crop  and  proper  methods  of  drying,  and, 
of  course,  again,  depending  upon  the  locality,  different  methods 
will  be  followed.  There  are  some  places  at  certain  times  where 
it  would  be  quite  possible  to  dry  the  drugs  out  of  doors.  In  other 
situations  it  would  be  necessary  to  dry  them  in  barns  and  even 
in  specially  constructed  drying  ovens*  where  artificial  heat  would 
be  employed.  The  drying  oi  leaves,  flowers,  and  seeds  is  com- 
paratively simple  and  can  usually  be  rather  quickly  performed 
without  any  special  preparation.  In  the  case  of  roots  and  fleshy 
fruits  the  drying  should  be  under  special  protection,  and  is  facili- 
tated more  or  less  by  slicing  or  comminuting  the  article. 

In  some  drugs,  in  addition  to  drying,  there  is  a  curing  process 
that  takes  place.  By  this  process  of  fermentation  the  active  con- 
stituents are  developed.  Among  the  drugs  treated  in  this  manner 
the  following  may  be  mentioned :  tobacco,  vanilla,  gentian, 


CULTIVATION  OF  MEDICINAL  PLANTS.        739 

guarana,  digitalis,  the  Solanaceous  leaves,  etc.  In  some  cases 
the  increase  in  quality  can  be  determined  by  the  assay  of  some  one 
constituent,  but  in  other  cases  the  acquired  value,  like  that  of  teas, 
wines,  and  tobacco,  cannot  be  determined  by  an  assay  process  and 
yet  can  be  detected  by  the  expert. 

It  has  already  been  pointed  out  that  plants  contain  a  large 
proportion  of  water,  and  when  they  are  collected  and  dried  there 
is  necessarily  considerable  loss.  The  loss  is  greater  in  the  case 
of  herbaceous  plants,  where  the  yield  of  crude  drug  is  only  about 
10  per  cent.,  as  in  eupatorium  and  stramonium.  Roots  and  rhi- 
zomes yield  on  an  average  from  20  to  30  per  cent,  of  dried  drug. 
In  some  cases,  as  in  hops,  the  yield  of  dried  drug  is  over  60  per 
cent.,  and  in  fruits  and  seeds  there  is  very  little  loss. 

RELATIVE  VALUE  OF  DRUGS  FROM  CULTIVATED  AND  WILD 
PLANTS. — For  some  years  it  has  been  a  question  whether  the 
activity  of  drugs  obtained  from  cultivated  plants  is  equal  to  that 
of  those  derived  from  wild  plants.  We  find  in  some  of  the 
foreign  pharmacopoeias  the  specific  statement  that  certain  drugs, 
as  digitalis,  belladonna  leaves,  and  belladonna  root,  must  be 
derived  from  wild  plants.  This  would  naturally  lead  to  the  infer- 
ence that  wild  plants  are  better,  and  yet  it  may  be  that  this 
provision  was  made  with  the  intention  of  securing  uniformity 
of  drugs  rather  than  because  the  materials  from  wild  plants  are 
superior.  In  1907  Rippetoe  conducted  some  experiments  in  Vir- 
ginia which  showed  that  cultivated  plants  of  belladonna  yielded 
both  leaves  and  roots  which  were  equal,  if  not  superior,  to  the 
average  drug  on  the  market.  As  this  work  was  done  without  any 
particular  care  and  in  a  limited  way,  it  was  more  than  gratifying 
to  those  who  were  especially  interested  in  this  subject.  Carr  has 
shown  by  careful  comparative  experiments  that  cultivated  plants 
of  belladonna  contain  a  little  more  alkaloid  than  do  the  wild 
plants.  The  investigations  of  Sievers  also  point  to  a  similar 
conclusion.  Sievers  has  also  shown  that  the  percentage  of  alka- 
loids in  the  leaves  of  different  cultivated  plants  is  exceedingly 
large,  and  that  plants  high  in  alkaloids  will  continue  to  breed 
plants  high  in  alkaloids,  so  that  by  mere  selection  a  better  com- 
mercial article  may  be  produced.  Coming  to  the  question  of 
digitalis,  there  are  some  very  interesting  results.  Hale,  for  in- 


740 


A  TEXT-BOOK  OF  BOTANY. 


stance,  showed  that  cultivated  digitalis  leaves  yield  a  much  higher 
potency  than  those  obtained  from  wild-grown  plants,  and  yet 
he  concludes  that  it  is  doubtful  whether  the  fact  that  they  were 
cultivated  had  anything  to  do  with  the  high  activity.  One  of  the 
most  valuable  facts  brought  out  in  connection  with  these  experi- 
ments is  that  the  leaves  of  one-year-old  plants  seem  to  have  as  great 
toxicity  as  those  of  the  two-year-old  plants.  Hale  distinctly  states 
that  "  first-year  leaves  are  not  necessarily  weaker  than  second- 


FlG.  408.  Atropa  Belladonna,  first  year's  growth  from  seed  planted  January  ist. 
Photograph  in  July  of  the  same  year. — From  the  Experimental  Farm  of  Eli  Lilly  &  Com- 
pany, Indianapolis,  Ind. 

year  leaves,  and  might  be  used  in  preparing  assayed  digitalis  prepa- 
rations." This  means  that  one  does  not  have  to  wait  two  years 
before  securing  a  crop,  so  that  practically  one  can  obtain  twice  the 
quantity  of  the  drug  during  the  same  period. 

There  may  be  some  instances  during  this  experimental  stage 
which  might  seem  to  indicate  that  certain  external  conditions,  such 
as  climate  as  well  as  soil,  have  a  very  great  influence  in  the  growing 
of  plants  o<f  exceptional  value.  In  the  case  of  American-grown 
cannabis,  Eckler  and  Miller  have  shown  that  repeated  plantings 


CULTIVATION  OF  MEDICINAL  PLANTS.        741 

from  carefully  selected  plants  of  American  and  Indian  cannabis 
have  failed  to  yield,  when  in  cultivation  near  Indianapolis,  a 
product  testing  over  65  per  cent,  of  the  active  value  of  good 
Indian-grown  drug,  and  that  the  majority  of  the  plants  tested 
50  per  cent,  and  even  less. 


FlG.  409.  Form  of  American  Cannabis  developed  by  F.  A.  Miller.  Such  forms  are 
obtained  by  selection  and  result  in  strains  that  are  better  adapted  to  modern  methods  of 
agriculture  and  from  which  the  collection  of  the  pistillate  inflorescence  is  greatly  simplified. — 
From  the  Experimental  Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

Experiments  conducted  near  Timmonsville,  S.  C,  by  the  U.  S. 
Department  of  Agriculture  have  shown  that  in  that  locality  a 
drug  of  a  somewhat  higher  degree  of  potency  can  be  grown.  Of 
course,  it  is  well  known  that  the  hemp  plant  is  grown  extensively 
for  fiber  in  Kentucky  and  other  parts  of  the  middle  West.  This 


742 


A  TEXT-BOOK  OF  BOTANY. 


may  be  due  in  large  part  to  the  fact  that  it  requires  a  limestone  soil, 
and  in  practice  the  most  favorable  results  are  obtained  where  there 
is  an  underlying  bed  of  blue  limestone.  Sufficient  has  been  said 
to  show  that  success  will  attend  the  cultivation  of  medicinal 
plants,  and  indeed,  by  a  priori  reasoning  on  the  basis  of  other 


FlG.  410.  Form  of  American  Cannabis  developed  by  F.  A.  Miller.  Such  forms  are 
obtained  by  selection  and  result  in  strains  that  are  better  adapted  to  modern  methods  of 
agriculture  and  from  which  the  collection  of  the  pistillate  inflorescence  is  greatly  simplified. 
— From  Experimental  Farm  of  Eli  Lilly  &  Company,  Indianapolis,  Ind. 

agricultural  efforts,  one  would  expect  that  medicinal  plants  could 
be  grown  with  the  same  certainty  of  increasing  the  yields  of  any 
particular  constituent  or  quality  that  might  be  desired.  Indeed, 
the  history  o<f  the  sugar  beet  industry  has  been  duplicated  in  the 
work  on  Cinchona,  and  the  same  thing  can  be  said  with  regard  to 
any  other  plant  that  man  desires  to  conserve  and  cultivate.  There 


CULTIVATION  OF  MEDICINAL  PLANTS.        743 


are  no  insurmountable  obstacles  in  this  work,  and  there  are  no  in- 
tricate processes  to  be  solved  before  success  results.  There  are 
merely  a  few  underlying  principles  that  must  be  adhered  to,  and 
by  persistent  effort  and  with  a  full  understanding  of  market  con- 
ditions success  must  crown  the  efforts  of  anyone  who  undertakes 


FIG.  411.     A  seedling  plant  of  Digitalis  about  six  months  old. 

this  work.  What  has  been  done  in  the  selection  of  fruits  and  vege- 
tables can  be  equally  well  accomplished  in  drugs  with  the  proper 
incentive. 

PROGRESS  IN  THE  UNITED  STATES. — We  can  scarcely  appreciate 
that,  while  the  development  of  medicinal  plant  culture  has  been 


744 


A  TEXT-BOOK  OF  BOTANY. 


an  exceedingly  slow  one,  yet  as  a  matter  of  fact,  by  reason  of 
some  of  the  products  being  more  extensively  used,  as  in  the  case 
of  hops,  it  is  one  of  the  oldest  agricultural  industries  in  the  United 
States.  The  history  of  the  cultivation  of  hops  is  very  similar  to 


FIG.  412. 


Cannabis  sativa:  Young  plant  grown  from  seed  found  in  the  drug  Cannabis 
indica. 


the  experience  with  other  medicinal  plants.  For  instance,  it  was 
grown  in  Virginia  with  poor  results,  and  in  Vermont  and  Massa- 
chusetts, where  it  was  very  successful.  By  virtue  of  the  success 
obtained  in  the  New  England  States  it  was,  in  the  early  part  of 
the  last  century,  introduced  into  New  York  State  and  later  spread 


CULTIVATION  OF  MEDICINAL  PLANTS.        745 

into  some  of  the  Middle  States,  as  Michigan,  Wisconsin,  Indiana, 
and  Ohio.     Since  that  time  the  cultivation  has  been  extended  to 


FIG.  413.     Seedling  plants  of  Erythroxylon  Coca  (A)  and  Eucalyptus  globulus  (B). 

some  of  the  States  on  the  Pacific  coast,  notably  Oregon,  Washing- 
ton, and  northern  California. 

The  peppermint  industry  shows  a  similar  history.    This  indus- 
try was  first  developed  in  Wayne  County,  New  York.    Later  it 


746  A  TEXT-BOOK  OF  BOTANY. 

spread  into  Michigan,  Ohio,  and  some  of  the  Southern  States, 
and  by  reason  of  the  more  favorable  climate  and  soil  conditions 
in  Michigan  the  industry  here  has  outstripped  that  of  even  New 
York  State,  being  practically  .abandoned  in  Ohio  and  the  other 
States.  The  men  connected  with  the  Division  of  Botany  of  the 
United  States  Department  of  Agriculture  have  always  mani- 
fested a  keen  interest  in  the  possibilities  of  the  cultivation  of 
medicinal  plants,  and  have  done  what  they  could  to  encourage 
interest  in  this  subject,  and  the  records  show  that  they  have  sup- 
plied in  formation  as  it  might  be  needed  by  those  disposed  to  take 
up  the  work  in  a  practical  manner. 

The  development  of  the  tea  industry  in  North  Carolina  is 
one  of  the  most  creditable  pieces  of  work  of  the  National  Govern- 
ment. Bulletin  No.  234  of  the  Bureau  of  Plant  Industry,  on  "  The 
Cultivation  and  Manufacture  of  Tea  in  the  United  States,"  by 
George  F.  Mitchell,  should  serve  as  an  inspiration  to  anyone 
contemplating  drug  culture.  If  a  plant  of  this  kind  can  be  grown 
successfully  here  and  the  technique  of  manufacture  developed 
to  such  an  extent  that  the  cultivation  at  Pinehurst,  North  Carolina, 
has  become  remunerative,  there  is  no  question  but  that  within 
reasonable  limits  nearly  any  plant  except  the  strictly  tropical  ones 
can  be  successfully  grown  in  the  United  States. 

Without  doubt,  the  camphor  industry  will  become  successful 
in  some  of  the  Southern  States.  Nearly  fifty  years  ago,  when  the 
price  of  camphor  was  very  high,  the  government  started  some 
experiments  in  Florida  in  the  growing  of  the  camphor  tree.  These 
experiments  were  subsequently  abandoned,  as  there  was  hardly 
any  likelihood  of  anyone  being  interested  in  this  commercially 
on  account  of  the  low  price  of  camphor.  During  the  past  few 
years,  however,  interest  in  this  culture  has  been  revived  in  Florida 
and  southern  Georgia.by  reason  of  the  fact  that  frosts  destroyed  the 
citrus  fruits  and  the  landowners  began  a  search  for  other  possible 
crops  which  would  not  be  so  injured.  Circular  No.  12,  Division 
of  Botany,  United  States  Department  of  Agriculture,  shows  just 
what  can  be  done  for  the  successful  cultivation  of  this  tree  in  the 
Southern  States,  and  some  recent  experiments  of  the  government 
show  that  by  utilization  of  leaves  and  twigs  there  are  great  possi- 
bilities in  the  economical  manufacture  of  camphor  in  the  United 
States  in  spite  of  the  high  price  of  labor. 


CULTIVATION  OF  MEDICINAL  PLANTS.        747 

Owing  to  the  fact  that  essential  oils  are  used  in  such  large 
quantities  it  is  quite  likely  that  the  cultivation  of  many  of  these 
plants  may  be  made  successful,  providing  at  the  same  time  that 
suitable  apparatus  for  their  distillation  is  also  installed  upon  the 
farms. 

By  reason  of  the  fact  that  the  cultivation  of  chicory  is  a  per- 
manent agricultural  industry  in  nearly  all  of  the  countries  having 
a  temperate  climate  in  Europe,  experiments  have  been  conducted 
in  the  United  States  in  a  small  way,  and  these  have  led  to  the  con- 
clusion that  it  may  be  successfully  cultivated  in  those  States  where 
the  sugar  beet  industry  has  flourished. 

As  a  summary,  the  following  general  points  might  be  held  in 
mind  by  those  who  desire  to  take  up  the  cultivation  of  medicinal 
plants : 

In  the  first  place,  he  ought  to  determine  whether  there  is  a 
market  for  any  drug  under  consideration,  and  this  can  only  be 
obtained  by  personal  inquiry  and  investigation,  as  not  even  any 
of  the  government  publications  give  this  information. 

In  the  next  place,  if  one  is  satisfied  that  it  is  worth  while 
to  take  up  the  cultivation  of  any  particular  plant,  its  geographi- 
cal range  should  be  studied,  both  as  to  where  it  is  indigenous 
and  where  it  has  become  naturalized.  The  literature  should  be 
gone  over  not  only  for  facts  regarding  the  cultivation  and  distribu- 
tion of  the  particular  plant  in  view,  but  also  of  some  of  the  related 
plants. 

At  the  same  time  that  these  preliminary  studies  are  made,  a 
careful  survey  should  be  taken  of  the  plants  which  are  indigenous 
and  under  cultivation  in  the  particular  locality  where  one  is  pro- 
posing to  locate  the  farm.  Then,  of  course,  everything  should 
be  done  on  a  small  scale  at  first.  If  there  is  no  information 
available,  then  he  must,  on  the  basis  of  the  general  principles  laid 
down  for  the  cultivation  of  medicinal  plants,  proceed  with  their 
culture,  conducting  parallel  experiments  with  propagation  by  both 
seeds  and  cuttings. 

Then  when  the  crop  is  harvested  he  must,  by  analytical  and 
other  means,  satisfy  himself  as  to  the  value  of  his  product  com- 
pared with  the  commercial  article,  and  with  these  facts  in  hand 
submit  specimens  and  request  quotations  from  the  dealer  in  crude 
drugs,  and  the  wholesale  druggist.  On  this  basis  he  will  arrange 


748  A  TEXT-BOOK  OF  BOTANY. 

for  all  future  crops  with  some  certainty  as  to  their  market  value. 
Experience  has  shown  that  cultivated  crops  command  a  higher 
price  than  the  drugs  obtained  from  wild  plants,  even  though  their 
superiority  cannot  always  be  demonstrated  by  analytical  means. 
For  instance,  no  one  is  trying  to  determine  by  an  analytical  process 
whether  any  given  lot  if  tobacco,  tea,  or  coffee  is  of  superior  value, 
and  yet  the  competent  dealer  and  the  discriminating  public  even 
recognize  the  qualities  of  the  grades  that  are  offered.  This  is 
even  more  marked  with  the  products  that  have  been  derived  thus 
far  from  cultivated  medicinal  plants,  and  are  appreciated  by  some 
pharmacists  and  physicians. 

BIBLIOGRAPHY. 

CULTIVATION  OF  BELLADONNA  :  A.  F.  Sievers,  Amer.  Jour.  Pharm.,  March 
and  November,  1914;  Francis  H.  Carr,  Ibid.,  November,  1913;  F.  A. 
Miller,  Ibid.,  July,  1913. 

CULTIVATION  OF  DIGITALIS:  E.  L.  Newcomb,  Amer.  Jour.  Pharm.,  No- 
vember, 1911 ;  John  A.  Bornefnan,  Ibid.,  December,  1912;  F.  A.  Miller, 
Ibid.,  July,  1913. 

CULTIVATION  OF  HYDRASTIS  :  John  Uri  Lloyd,  Proc.  A.  Ph.  A.,  1905,  p.  307, 
and  in  Jour.  A.  Ph.  A.,  Vol.  I,  p.  5;  Alice  Henkel  and  G.  Fred. 
Klugh,  Circ.  No.  6,  Bureau  of  Plant  Industry,  U.  S.  Department  of 
Agriculture;  J.  C.  Baldwin,  Amer.  Jour.  Pharm.,  April,  1913. 

CULTIVATION  OF  GINSENG  :  George  V.  Nash,  Bulletin  No.  16,  Division  of 
Botany,  U.  S.  Department  of  Agriculture. 

CULTIVATION  OF  EUCALYPTUS  :  A.  J.  McClatchie,  Bulletin  No.  35,  Bureau 
of  Forestry,  U.  S.  Department  of  Agriculture. 

CULTIVATION  OF  PEPPERMINT:  A.  M.  Todd,  Proc.  A.  Ph.  A.,  1903,  p.  277; 
Alice  Henkel,  Bulletin  No.  90,  Bureau  of  Plant  Industry,  U.  S.  De- 
partment of  Agriculture. 

CULTIVATION  OF  CANNABIS  SATIVA  :  C.  R.  Eckler  and  F.  A.  Miller,  Amer- 
Jour.  Pharm.,  November,  1912. 

CULTIVATION  OF  CAMPHOR  :  Circ.  No.  12,  Division  of  Botany,  U.  S.  De- 
partment of  Agriculture. 

CULTIVATION  OF  TEA  :  Bulletin  234,  Bureau  of  Plant  Industry,  U.  S.  De- 
partment of  Agriculture. 

CULTIVATION   OF   CHICORY:    Bulletin   No.    19,   Division   of   Botany,   U.    S. 
Department  of  Agriculture. 
A  number  of  valuable  articles  by  Mitlacher  and  other  members  of  the 

pharmacognostical   department   of    the    University   of   Vienna   have   been 

published    in    Zeitschrift   fur    das    landwirtschaftliche    Versuchswesen   in. 

Oesterreich  since  1911. 


CHAPTER  VII. 
MICROSCOPIC  TECHNIQUE  AND  REAGENTS. 

MAKING  OF  SECTIONS. — In  order  to  examine  objects  by  means 
of  the  compound  microscope  they  must  be  relatively  thin  and 
transparent ;  furthermore,  they  must  be  mounted  in  water  or  other 
mounting  fluids.  In  material  consisting  of  single  cells,  or,  at 
most,  a  layer  of  a  few  cells,  the  specimen  may  be  mounted  directly 
in  water.  This  manner  of  mounting  may  also  be  used  in  the  exam- 
ination of  pollen  grains,  hairs,  and  thin  organs,  as  petals.  Usually 
in  the  examination  of  the  latter  some  clearing  agent,  as  solution  of 
hydrated  chloral,  is  necessary  in  order  to  make  the  specimen  trans- 
parent. As  most  objects  consist  of  a  large  number  of  cells,  it  is 
necessary  to  examine  small  portions  of  them,  and  these  are  termed 
sections.  They  are  made  with  a  razor  and  correspond  to  the  shav- 
ings made  by  a  carpenter's  plane.  As  each  object  has  three  dimen- 
sions, it  is  necessary  that  three  different  kinds  of  sections  be  made. 

1 i )  A  transverse  or  cross  section  is  one  made  horizontally  through 
the  object,  therefore  its  plane  lies  at  right  angles  to  the  long  axis* 

(2)  A  radial-longitudinal  section  is  one  made  at  right  angles  to  the 
cross  section  and  it  lies  in  the  plane  of  the  radius,  so  that  in  a 
dicotyledonous  stem  the  section  would  be  made  parallel  with  the 
medullary   rays.      (3)    A   tangential-longitudinal   section   differs 
from  the  preceding  in  that  it  lies  parallel  to  the  outer  surface  of 
the  object,  or  in  a  plane  tangent  to  the  cylinder.     These  several 
forms  of  sections  are  readily  understood  from  the  adjoining  illus- 
tration (Fig.  414). 

Sections  of  roots,  stems,  barks,  and  many  fruits  and  seeds 
can  be  made  directly  without  embedding  the  material,  and  while 
sections  can  be  made  holding  the  material  in  the  hand,  between 
the  thumb  and  three  fingers,  the  hand  microtome  for  holding 
the  material  may  be  used  by  those  who  are  less  experienced.  In 
the  sectioning  of  leaves  and  other  material  that  is  not  firm,  and 
fruits  and  seeds  which  are  too  small  to  hold  in  the  hand,  the 
material  should  be  embedded  in  some  substance  which  will  hold 
it  and  give  it  stability.  When  the  tissues  are  not  too  hard  the 

749 


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A  TEXT-BOOK  OF  BOTANY. 


material  may  be  placed  between  pieces  of  elder  or  sunflower  pith. 
In  some  cases  the  making  of  sections  is  facilitated  by  moistening 
both  the  pith  and  the  razor.  In  the  case  of  seeds  and  fruits  which 
are  very  small  and  at  the  same  time  very  hard,  as  colchicum  and 
mustard,  it  is  best  to  use  a  velvet  or  fine  grade  of  cork  for  holding 
the  material.  The  cork  is  indented  by  means  of  forceps  and  the 
seed  or  fruit  forced  into  the  cavity. 

In  the  case  of  very  delicate  tissues,  where  the  protoplasmic 
contents  of  the  cells  are  to  be  studied,  as  in  the  ovaries  of  flowers, 
prothalli  of  ferns  and  other  parts  of  the  plant,  where  cell  division, 
is  going  on,  the  material  should  be  embedded  in  paraffin  or  celloi- 


FIG.  414.    Schematic  presentation  of  the  three  types  of  sections:  q,  cross  or  transverse  sec- 
tion; /,  radial-longitudinal  section;  /,  tangential-longitudinal  section. — After  Meyer. 


din,  subsequently  hardened,  and  sectioned  by  means  of  a  finely 
adjusted  microtome. 

DRIED  MATERIAL. — Most  of  the  vegetable  drugs  and  some  of 
the  vegetable  foods  occur  in  commerce  in  a  more  or  less  dried 
condition,  and  in  order  to  study  them  microscopically  it  is  usually 
necessary  to  give  them  some  preliminary  treatment.  With  the 
majority  of  drugs,  soaking  in  hot  or  cold  water  from  a  few 
minutes  to  a  few  hours  will  render  them  sufficiently  pliable  or 
soft  for  sectioning.  After  this  the  material  is  hardened  by  placing 
it  in  alcohol  (60  to  70  per  cent.)  for  a  few  hours  or  over  night. 
It  may  then  be  sectioned  and  treated  with  special  reagents  or 
stains  as  desired.  Very  hard  material,  as  the  shells  of  nuts  and 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.    751 

seeds,  may  be  softened   by   soaking   in   solutions   of   potassium 
hydrate. 

SOME  PRACTICAL  SUGGESTIONS. — The  following  are  some 
of  the  rules  which  should  be  bo-rne  in  mind  by  the  student 
when  using  the  microscope  in  the  examination  of  microscopic 
material : 

1.  Always  mount  the  sections  (including  powdered  material) 
in  water  or  other  suitable  reagent  prior  to  examination;  never 
attempt  to  examine  dry  material  except  in  special  cases. 

2.  Use  sufficient  of  the  mounting  medium  or  reagent  to  cover 
the  specimen,  but  avoid  an  excess  or  more  than  will  be  held  under 
the  cover-glass. 

3.  Always  endeavor  to  have  the  object  properly  illuminated 
by  making  use  of  the  concave  mirror. 

4.  Always  be  particular  about  having  the  eye-piece  and  objec- 
tives clean. 

5.  In  examining  a  microscopic  object,  always  use  the  low- 
power  objective  first. 

6.  The  edge  of  a  section  is  always  the  thinnest,  and  this  part 
being  the  best  for  study,  should  be  brought  to  the  center  of  the 
field. 

7.  When  the  object  is  properly  centered,  raise  the  objective, 
swing  it  to  one  side,  bring  the  high-power  objective  into  its  place, 
and  cautiously  lower  it  until  it  is  brought  to  about  the  distance 
of  a  millimeter  from  the  cover-glass.     Then  holding  the  slide 
with  the  left  hand,  the  proper  focus  of  the  object  is  obtained  by 
making  use  first  of  the  coarse  adjustment  and  then  of  the  fine 
adjustment,  the  right  hand  being  used  fo-r  this  purpose.    In  exam- 
ining the  object  always  hold  the  slide  with  the  left  hand,  and 
use  the  right  hand  for  maintaining  the  proper  focus  by  means  of 
either  the  coarse  or  fine  adjustment. 

8.  In  all  cases  where  practicable  make  drawings  of  the  sections 
examined. 

9.  In  some  cases  it  is  desirable  to  apply  a  reagent  after  the 
material  has  been  mounted,  as  in  the  addition  of  an  iodine  solution 
to  a  section  to  determine  the  presence  of  starch,  and  this  is  accom- 
plished by  placing  a  drop  or  two  of  the  reagent,  by  means  of  a 
pipette  or  dropper,  near  the  edge  of  the  cover  on  one  side  and 


752 


A  TEXT-BOOK  OF  BOTANY. 


taking  up  the  excess  of  liquid  by  temporarily  placing  a  piece  of 
filter  paper  on  the  opposite  side  (Fig.  415). 

AIR-BUBBLES. — The  beginner  in  the  use  of  the  microscope  is 
often  confused  by  the  presence  of  air-bubbles,  mistaking  them 
for  portions  of  the  material  under  examination,  as  starch  grains, 
oil-globules,  or  even  the  cells  themselves.  While  it  is  not  prac- 


FIG.  415.     Method  of  applying  reagent  to  material  already  mounted,     g,  pipette;    f, 

filter  paper. 

ticable  to  avoid  their  presence  entirely,  their  identity  may  be 
determined  by  the  manner  of  focussing  upon  them.  When 
focussing  above  on  an  air-bubble  it  always  appears  dark  (Fig. 
416,  C),  but  when  the  focus  is  lowered,  it  becomes  lighter  (Fig. 
416,  D)  ;  while  in  the  case  of  an  oil-globule  or  starch  grain  the 
reverse  is  true,  i.e.,  it  is  lightest  when  the  focus  is  above  (Fig. 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   753 

416,  E)  and  darker  when  the  focus  is  lowered  (Fig.  416,  F). 
To  obviate  as  much  as  possible  the  formation  of  air-bubbles,  the 
edge  of  the  cover-glass  should  first  be  applied  to  the  liquid  on  one 
side  and  then  allowed  to  drop  upon  it.  When  particular  care  is 
required,  a  pair  of  forceps  may  be  used  for  holding  the  cover  and 
lowering  it  gradually. 


FIG.  416.  Diagrams  showing  the  difference  between  an  air-bubble  and  an  oil-globule 
in  different  foci:  When  the  focus  is  above,  as  at  A,  the  air-bubble  (C)  is  dark  gray  and 
the  oil-globule  (E)  light  gray.  When  the  focus  is  at  the  lower  portion,  as  at  B,  the  air- 
bubble  (D)  is  light  in  the  center  and  the  oil-globule  (F)  dark  gray.  The  same  optical  effects 
as  are  obtained  with  oil-globules  are  observed  with  cell  walls,  starch  grains  and  crystals. 

Frequently  also  simple  pores  in  the  cell-walls  are  mistaken 
for  cell-contents,  and  sometimes  even  the  lumen  of  the  cell  has 
been  mistaken  for  a  prism  of  calcium  oxalate.  The  beginner 
will  therefore  find  it  an  advantage  to  study  the  simple  pores  in 
the  pith  cells  of  elder  or  sassafras  (Fig.  132).  In  sections  show- 
ing either  the  upper  or  lower  wall  of  the  cells,  the  pores  appear 
as  circular  or  elliptical  markings,  which  may  be  mistaken  for  cell- 
48 


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A  TEXT-BOOK  OF  BOTANY. 


contents,  but  which  in  focussing  upon  them  are  seen  to  be  optical 

or  microscopical  sections  of  the  pores. 

MICROMETRY  OR  MICROSCOPIC  MEASUREMENT. — In  the  micro- 
scopic  study  of  any  substance  a  knowl- 
edge of  the  comparative  size  of  the 
elements  is  often  of  much  help  in  deter- 
mining the  identity  of  material  under 
examination,  and  for  this  reason  the 
student  should  early  learn  to  measure  the 
characteristic  elements,  or  those  showing 
a  variation  in  size  in  different  plants,  as 
starch  grains,  calcium  oxalate  crystals, 
diameter  of  cells,  thickness  of  cell-walls, 
etc.  The  method  best  adapted  for  this 
work  is  that  involving  the  Use  of  a  micro- 
metric  scale  which  is  placed  in  the  eye- 
piece and  known  as  the  ocular  micrometer. 
But  to  determine  the  value  of  the  ocular 
micrometer  it  is  necessary  to  use  another 
scale  known  as  the  stage  micrometer. 
The  stage  micrometer,  as  its  name  indi- 
cates, is  used  on  the  stage,  and  when 
placed  in  juxtaposition  to  an  object  indi- 
cates its  size.  However,  it  is  obviously 
impracticable  always  to  place  an  object 

alongside  of  the  scale,  and  hence  in  prac- 

Cjhit^ _...^  tice  the   ocular  micrometer   is   used,   the 

value    of    the    divisions    of    which    are 

of  determined  by  comparison  with  those  of 

the  ocular  micrometer  (o)  and  ..i  •  /T-"  \  TM 

the  stage  micrometer  (s).   AS  the   stage   micrometer    (Fig.   417).      The 

here  represented    20  divisions         1  r    j_i         j'     •    •  r    j.i  1  1 

of  the  ocular  scale  are  equiva-  Value  of  the  divisions  of  the  OCUlar  Scale 
lent  to  4  divisions  of  the  stage  •  e  j  •  rr  i  •  ,  • 

micrometer,  and  thus  each  di- vanes  for  different  objectives,  eye-pieces 

vision  of  the  ocular  is  equiva-  1^.11          ^i         1  •,     • 

lent  to  2  microns  (see  p.  8i3).  and  tube  lengths,  hence  it  is  necessary  to 

d,    diaphragm    in    eye-piece,  ,     •       ,1  i  f   ,1         «...  r  . 

on  which  the  ocular  microm-  ascertain  the  value  of  the  divisions  for  the 
different    optical    combinations    and    tube 

lengths  employed.  The  stage  micrometer  is  usually  divided  into 
tenths  and  hundredths  of  a  millimeter,  and  the  millimeter  being 
equivalent  to  1000  microns  (the  micron  being  indicated  by  the 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   755 

Greek  letter  ^u.),  the  smaller  divisions  are  equivalent  to  10  microns 
(io/x).  For  example,  suppose,  using  a  low-power  objective, 
that  10  divisions  of  the  ocular  scale  equal  20  of  the  smaller 
divisions  of  the  stage  micrometer.  Thus,  20  divisions  of  the  stage 
micrometer  are  equivalent  to  20  times  IO/A  ,  or  200 /x;  then,  since 
10  divisions  of  the  ocular  scale  equal  20  divisions  of  the  stage 
micrometer,  one  division  of  the  ocular  scale  is  equivalent  to  i/io 
of  200 /x,  or  20  fji.  Or,  using  the  high-power  objective,  we  may 
suppose  that  80  divisions  of  the  ocular  scale  equal  24  divisions  of 
the  stage  micrometer.  Thus,  I  division  of  the  ocular  micrometer 
is  equivalent  to  1/80  of  240 /z,  or  3^.  Then,  if  an  object  has  a 
diameter  covering  3  divisions  of  the  ocular  micrometer,  its  diame- 
ter is  equivalent  to  3  times  3  /*  (the  value  of  one  division),  or  9  p. 

REAGENTS. — The  reagents  that  have  been  recommended  for 
microscopical  work  are  quite  numerous,  and,  while  nearly  all  o-f 
them  may  have  more  or  less  special  merit,  the  number  of  reagents 
actually  required  in  practice  is  fortunately  quite  small. 

It  is  important  that  the  student  recognize  the  necessity  for  a 
thorough  understanding  of  the  structure  of  the  material  under 
examination  rather  than  place  too  much  dependence  upon  the 
effects  produced  by  reagents ;  in  other  words,  the  study  of  struc- 
ture should  precede  the  use  of  reagents,  particularly  stains,  when 
it  will  often  be  found  that  the  latter  can  be  dispensed  with  entirely. 

The  chemicals  that  are  employed  in  microscopical  work,  either 
as  reagents  or  for  other  purposes,  may  be  classified  as  follows: 
(i)  Preservatives,  (2)  Fixing  and  Killing  Agents,  (3)  Harden- 
ing and  Dehydrating  Agents,  (4)  Clearing  Agents,  (5)  Stains, 
and  (6)  Special  Reagents. 

PRESERVATIVES  are  substances  used  to  preserve  material  which 
is  to  be  examined.  The  most  important  of  these  are  alcohol  ( from 
40  to  95  per  cent.)  and  formalin  [2  to  6  per  cent,  aqueous  or 
alcoholic  (60  per  cent,  alcohol)  solution],  the  latter  of  which  is 
considered  advantageous  in  the  preservation  of  specimens  contain- 
ing coloring  substances,  as  leaves,  flowers,  etc.  Almost  any  anti- 
septic of  the  proper  strength  may  be  used  as  a  preservative. 

FIXING  or  KILLING  AGENTS  are  more  especially  employed  in 
the  study  of  the  protoplasmic  cell-contents,  where  by  their  use 
the  life-processes  of  the  cell  are  brought  to  a  sudden  termination, 


756  A  TEXT-BOOK  OF  BOTANY. 

the  object  being  to  fix  the  contents  in  a  condition  approaching  as 
nearly  as  possible  the  normal  living  state.  In  order  to  carry  out 
this  operation  successfully,  the  living  specimen  must  be  placed  in 
the  fixing  or  killing  agent  as  soon  as  collected,  and  if  the  specimen 
is  large  it  should  be  cut  into  small  pieces.  The  following  are  some 
of  the  common  fixing  agents :  Chromic  acid  in  0.5  to  i  per  cent, 
aqueous  solution ;  osmic  acid  in  i  to  2  per  cent,  aqueous  solution ; 
Flemming's  mixture,  which  is  an  aqueous  solution  of  chromic 
acid  (0.25  per  cent.)  containing  o.i  per  cent,  of  osmic  acid  and 
o.i  per  cent,  of  acetic  acid;  picric  acid  in  concentrated  aqueous 
or  alcoholic  solution  ;  picric-sulphuric  acid,  a  concentrated  aqueous 
solution  of  picric  acid  containing  2  per  cent,  by  volume  of  sulphuric 
acid;  and  mercuric  chloride  (corrosive  sublimate)  used  in  o.i  to 
i  per  cent,  aqueous  or  alcoholic  solution. 

HARDENING  or  DEHYDRATING  AGENTS  are  those  substances 
which  are  employed  for  the  purpose  of  hardening  the  specimen  so 
as  to  facilitate  sectioning  and  for  removing  the  water,  which 
would  interfere  with  its  examination.  Alcohol  is  to  be  regarded 
as  the  principal  hardening  or  dehydrating  agent,  and  considerable 
care  is  necessary  in  its  use;  the  specimen  is  treated  successively 
with  alcoholic  solutions  of  gradually  increasing  strength,  begin- 
ning with  a  35  per  cent,  solution,  in  which  the  specimen  is  kept 
for  twenty-four  hours ;  then  it  is  placed  in  50  per  cent,  alcohol  for 
from  six  to  twenty-four  hours,  and  then  in  70  per  cent,  alcohol, 
in  which  it  may  be  kept  until  ready  for  use.  In  order  to  avoid 
shrinking  of  the  material  at  this  stage,  it  may  be  kept  in  a  solu- 
tion of  alcohol  and  glycerin,  or  oil  of  bergamot,  or  a  mixture  of 
xylol  and  paraffin.  When  the  material  is  to  be  examined  it  should 
be  removed  to  85  per  cent,  alcohol  for  from  six  to  twenty- four 
hours,  then  to  95  per  cent,  alcohol  and  absolute  alcohol  suc- 
cessively for  the  same  length  of  time.  Of  the  other  dehydrating 
agents  the  most  important  are  anhydrous  glycerin,  pure  carbolic 
acid,  and  anhydrous  sulphuric  acid,  the  latter  being  used  in  a 
desiccator  and  not  applied  directly  to  the  specimen. 

CLEARING  AGENTS. — Most  dehydrating  agents  are  also  clear- 
ing agents,  because  of  the  fact  that  the  air  and  water  in  the  speci- 
men are  replaced  by  a  medium  having  greater  refractive  proper- 
ties. Some  clearing  agents  act  chemically  on  the  tissues  and  cell- 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   757 

contents.  Among  the  clearing  agents  most  frequently  employed 
are:  Chloral  in  saturated  aqueous  solution,  and  chloral-glycerin 
solution  (a  solution  of  equal  parts  of  glycerin  and  water  saturated 
with  chloral).  Essential  oils,  as  clove,  turpentine,  cedar,  mar- 
joram, etc.,  are  also  useful  for  this  purpose,  particularly  when 
the  specimen  is  to  be  mounted  in  Canada  balsam. 

STAINING  AGENTS  are  those  that  produce  more  or  less  defi- 
nitely colored  compounds  with  the  cell-contents  or  -walls.  They 
include:  (i)  the  Aniline  Dyes  and  (2)  Non-aniline  Stains. 

The  aniline  stains  may  be  used  in  aqueous  solutions,  weak 
alcoholic  solutions  or  strong  alcoholic  solutions,  containing  from 
i  to  3  per  cent.  o>f  the  dye.  The  following  are  the  aniline  stains 
most  frequently  employed :  Aniline  blue,  Bismarck  brown,  fuchsin, 
gentian  violet,  methylene  blue,  methyl  violet  and  safranin.  In 
addition  to  these,  aniline  hydrochloride  or  sulphate  is  used  in  what 
is  known  as  Wiesner's  Reagent,  which  is  a  25  per  cent,  solution  of 
alcohol  containing  5  per  cent,  of  either  of  these  salts,  a  drop  of 
either  hydrochloric  or  sulphuric  acid  being  used  with  a  drop  of  the 
solution,  according  as  the  hydrochloride  or  sulphate  has  been  used. 

LOFFLER'S  METHYLENE  BLUE. — This  reagent  is  prepared  by 
adding  30  c.c.  of  a  concentrated  alcoholic  solution  of  methylene 
blue  to  100  c.c.  of  water  containing  10  milligrams  of  potassium 
hydrate. 

ZIEHL'S  CARBOL-FUCHSIN. — This  solution  is  prepared  by  add- 
ing 15  c.c.  of  a  concentrated  alcoholic  solution  of  fuchsin  to 
100  c.c.  o>f  water  containing  5  grams  of  carbolic  acid. 

ANILINE  DYES  are  usually  employed  in  concentrated  aqueous 
solution,  but  owing  to  the  difference  in  solubility  of  the  dyes  the 
solutions  vary  in  strength.  Saturated  solutions  of  eosin  or  gen- 
tian violet  may  be  prepared  by  dissolving  i  gram  of  the  dye  in 
100  c.c.  of  water,  while  to  make  a  saturated  solution  of  methylene 
blue  requires  0.400  Gm.  of  the  dye  to  100  c.c.  of  water.  Some 
investigators  prefer  to  replace  the  distilled  water  with  aniline 
water,  which  is  prepared  by  adding  about  3  grams  of  anilin  oil  to 
loo  c.c.  of  distilled  water. 

REAGENT  BOTTLE  FOR  STERILE  SOLUTIONS. — The  solutions  of 
the  aniline  dyes  as  ordinarily  prepared  deteriorate  more  or  less 
rapidly  and  are  usually  made  up  fresh  each  time  they  are  required 


758 


A  TEXT-BOOK  OF  BOTANY. 


for  use.  These  solutions,  as  well  as  other  reagents  that  are  prone 
to  decomposition,  may,  however,  be  kept  for  months  or  even  years 
by  preparing  them  with  care  and  keeping  them  in  a  special  kind 
of  bottle  (Fig.  418).  An  ordinary  bottle  may  be  used,  and  is 
fitted  with  a  rubber  stopper  perforated  so  as  to  allow  the  intro- 
duction of  two  glass  tubes.  These  tubes  are  bent  twice  at  right 
angles  and  the  free  ends  directed  downwards.  One  of  the  tubes 
is  connected  with  an  atomizer  bulb  and  serves  for  forcing  out  the 


FIG.  418.     Reagent  bottle  for  sterile  solutions. 

liquid.  A  small  plug  of  absorbent  cotton  is  placed  in  the  tube 
at  the  point  C,  so  as  to  filter  the  air.  This  may  be  improved  by 
blowing  a  bulb  in  the  tube  for  holding  the  cotton.  The  bottle 
should  be  sterilized  before  placing  the  solution  in  it,  and  the  solu- 
tion should  be  made  by  adding  the  dye  to  sterile  water  contained 
in  the  bottle.  The  solution  may  be  afterwards  further  sterilized 
by  means  of  steam  if  this  should  be  found  necessary,  as  in  this 
way  only  a  perfectly  sterile  solution  could  be  produced. 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.  759 


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760  A  TEXT-BOOK  OF  BOTANY. 

The  non-aniline  stains  give,  as  a  rule,  more  reliable  and  con- 
stant results  in  the  study  of  cell-walls,  as  in  the  roots,  stems,  and 
other  parts  of  the  plant,  than  the  aniline  stains.  They  include 
the  following: 

BEALE'S  CARMINE  SOLUTION,  which  is  made  as  follows :  Mix 
0.6  Gm.  carmine  with  3.75  Gm.  ammonia  water  (10  per  cent.)  ; 
heat  on  a  water-bath  for  several  minutes ;  then  add  60  Gm.  o-f 
glycerin,  60  Gm.  of  water  and  15  Gm.  of  alcohol,  and  filter. 

GRENACHER'S  BORAX-CARMINE  SOLUTION. — Dissolve  2  to  3 
Gm.  of  carmine  and  4  Gm.  of  borax  in  93  c.c.  of  water  and  then 
add  100  c.c.  of  alcohol  (70  per  cent.)  ;  shake  and  filter.  When 
this  stain  is  employed  the  sections  are  freed  from  an  excess  by 
the  use  of  alcoholic  solutions  of  borax  or  oxalic  acid. 

HOVER'S  PICRO-CARMINE  SOLUTION  is  made  by  dissolving 
carmine  in  a  concentrated  solution  of  neutral  ammonium  picrate. 
A  solution  of  carmine  and  picric  acid  is  known  as  Picro-Carmine 
Solution.  Carmine  solutions  give  to  cellulose,  the  nucleus  and 
proteins  a  red  color. 

CHLOR-ZINC-IODIDE  SOLUTION,  or  Schulze's  Cellulose  Reagent, 
consists  of  anhydrous  zinc  chloride,  25  Gm. ;  potassium  iodide,  8 
Gm.,  and  water,  8.5  Gm.,  to  which  as  much  iodine  is  added  as 
the  solution  will  dissolve.  This  reagent  gives  a  violet  color  with 
cell-walls  containing  cellulose.  Of  the  cell-contents,  starch  is  the 
only  one  which  is  affected  by  it,  being  colored  blue. 

BOHMER'S  HJEMATOXYLIN  SOLUTION  is  prepared  by  mixing 
Ithe  two  following  solutions  and  filtering  after  allowing  the  mix- 
ture to  stand  for  several  days:  (a)  one  part  of  a  3.5  per  cent, 
alcoholic  (95  per  cent.)  solution  of  hsematoxylin  and  (b)  three 
parts  of  a  0.4  per  cent,  aqueous  solution  of  potassium  alum. 

DELAFIELD'S  H^MATOXYLIN  SOLUTION,  which  is  also  incor- 
rectly called  "  Grenacher's  Hsematoxylin  Solution,"  is  made  by 
mixing  the  following  solutions:  (a)  Hsematoxylin  4  Gm.,  alcohol 
25  c.c.,  and  (b)  400  c.c.  of  a  saturated  aqueous  solution  o>f  ammo- 
nia alum ;  this  solution  is  exposed  to  the  light  for  three  or  four 
days,  filtered,  and  then  100  c.c.  each  of  glycerin  and  methyl  alco- 
hol are  added,  the  solution  allowed  to  stand  for  several  days  and 
finally  filtered.  An  excess  of  the  stain  is  removed  from  the  sec- 
tions by  subsequent  washing  either  with  a  2  per  cent,  alum  solution 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   761 

or  an  acidified  alcoholic  solution.  This  solution  gives  to  cellulose, 
lignin  and  the  protoplasmic  cell-contents  a  violet  color. 

IODINE  AND  POTASSIUM-IODIDE  SOLUTION  consists  of  iodine, 
2  Gm. ;  potassium  iodide,  6  Gm. ;  water,  100  c.c. 

IODINE  WATER  is  prepared  by  adding  as  much  iodine  to  dis- 
tilled water  as  it  will  dissolve  (about  i :  5000). 

CHLORAL-IODINE  SOLUTION  consists  of  a  saturated  aqueous 
solution  of  chloral,  to  which  iodine  is  added.  This  reagent  is 
useful  for  staining  the  starch  grains  in  the  chloroplasts. 

PHLOROGLUCIN  SOLUTION,  used  as  a  test  for  lignin,  is  a  0.5 
to  2  per  cent,  alcoholic  solution  of  phloroglucin,  which  is  used 
in  conjunction  with  hydrochloric  acid.  The  reagent  should  be 
protected  from  light. 

IRON  SOLUTIONS  are  aqueous  or  alcoholic  solutions  containing 
5  to  20  per  cent,  of  ferric  acetate  or  ferric  chloride.  These  are 
mostly  used  as  tests  for  tannin,  giving  either  a  bluish-black  or 
greenish-black  coloration  or  precipitate. 

COPPER-ACETATE  SOLUTION  is  a  j  per  cent,  aqueous  solution 
of  cupric  acetate.  It  is  the  most  distinctive  test  for  tannin,  par- 
ticularly with  fresh  material,  producing  a  reddish-brown  precipi- 
tate in  the  cells  containing  tannin.  The  fresh  material  should  be 
cut  into  small  pieces  and  immediately  placed  in  the  solution  of 
copper  acetate  and  allowed  to  remain  for  from  24  to  48  hours. 
The  excess  of  the  reagent  is  then  washed  out  and  the  material 
placed  in  alcohol. 

SCFULZE'S  MACERATING  SOLUTION  is  prepared  by  adding 
crystals  of  potassium  chlorate  from  time  to  time  to  warm  con- 
centrated nitric  acid.  It  is  employed  in  the  isolation  of  lignified 
cells.  The  material  is  allowed  to  remain  in  the  solution  for  a 
short  time  or  until  there  appears  to  be  a  disintegration  of  the 
tissues.  A  large  excess  of  water  is  then  added.  The  material  is 
carefully  washed,  the  cells  teased  apart  and  mounted  in  a  solution 
of  methyl ene  blue. 

SPECIAL  REAGENTS  comprise  all  those  substances  which  are 
employed  in  the  morphological  study  of  the  cells,  and  include 
solutions  of  the  alkalies  (o.i  to  6  per  cent.)  solutions  of  the 
mineral  acids,  which  may  be  weak  or  concentrated,  and  solutions 
of  organic  acids,  as  acetic  and  citric. 


762 


A  TEXT-BOOK  OF  BOTANY. 


DOUBLE  STAINING,  or  the  use  of  two  stains  in  the  examination 
of  a  specimen,  furnishes  not  only  a  means  of  beautifying  the  speci- 
men, but  also  has  a  certain  diagnostic  value.  The  following  are 
some  of  the  combinations  used:  (a)  aqueous  solutions  of  car- 
mine in  connection  with  alcoholic  solutions  of  iodine  green;  (b) 


o 


PlG.  419..  Crystals  of  some  of  the  common  reagents  which  not  infrequently  sepa- 
rate on  the  slide  and  may  be  mistaken  for  cell  contents:  A,  isotropic  crystals  of  chloral 
which  occur  in  cubes  about  10  /u.  in  diameter  or  long  needles  about  50  M  long;  B,  phloro- 
glucm  which  occurs  in  broad  rectangular  plates  or  ellipsoidal  discs  from  10  to  35  /u.  in  diam- 
eter which  are  doubly  refracting  with  a  play  of  colors;  C,  cubes  of  potassium  iodide  which 
&Te  isotropic;  D,  crystals  from  potassium  hydrate  solution  which  separate  in  broad  prisms 
and  branching  chains  that  are  doubly  refracting  and  give  marked  color  effects. 

alcoholic  solutions  of  hsematoxylin  and  safranin;  (c)  solutions  of 
eosin  and  methylene  blue;  (d)  solutions  of  fuchsin  and  methylene 
blue;  (e)  solutions  of  gentian  violet  and  Bismarck  brown. 

MOUNTING    OF    SPECIMENS. — Microscopic    preparations    or 
mounts  are  of  two  kinds:  they  may  serve  a  temporary  purpose 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   763 

only  or  they  may  be  prepared  so  as  to  serve  for  future  study, 
the  latter  being  known  as  PERMANENT  MOUNTS. 

In  taking  up  the  study  of  a  specimen  it  should  first  be  mounted 
in  water  and  examined  ;  then  the  water  may  be  replaced  by  a  weak 
aqueous  solution  of  glycerin  (5  to  10  per  cent.)  and  the  specimen 
examined  again.  After  this  preliminary  examination  other  agents 
and  reagents  may  be  employed.  Specimens  mounted  in  glycerin 
will  keep  for  several  days  and  even  months.  Generally  speaking, 
the  only  effect  which  the  glycerin  has  on  the  tissues  or  contents 
is  that  of  swelling  them,  which  is  obviated,  to  a  greater  or  less 
extent,  however,  if  the  glycerin  is  washed  out  after  an  exam- 
ination is  made. 

In  addition  to  the  methods  involving  the  use  of  glycerin,  there 
are  two  ways  of  making  permanent  mounts,  depending  upon  the 
employment  either  of  Canada  balsam  or  glycerin  jelly  as  the 
mounting  medium.  The  method  involving  the  use  of  the  latter 
is  the  simpler,  and  leaves  the  specimen  in  such  a  condition  that  a 
re-examination  with  reagents  can  be  made  if  desirable.  GLYCERIN- 
JELLY  mounts  are  made  as  follows :  Specimens  which  have  been 
previously  treated  are  transferred  to  glycerin  and  allowed  to 
remain  for  several  hours,  the  excess  of  glycerin  removed,  and 
the  specimen  transferred  to  a  warm  slide  on  which  a  drop  of 
glycerin  jelly *  has  been  placed.  The  preparation  is  warmed 
slightly  to  remove  air-bubbles,  and  a  warm  cover-glass  applied, 
care  being  taken  to  prevent  the  formation  of  air-bubbles.  Evap- 
oration of  the  glycerin  jelly  is  prevented  by  the  use  of  shellac 
cements,  asphalt  varnish  or  candlewax. 

The  following  method  may  be  used  for  the  preparation  of 
CANADA  BALSAM  MOUNTS:  The  specimen  is  cleared,  dehydrated 
by  the  use  of  alcohol  and  then  placed  in  chloroform  or  benzol.  The 
clearing  of  the  specimen  is  materially  assisted  by  placing  it  in 
oil  of  cloves  or  turpentine  prior  to  mounting  it.  A  drop  of  Canada 
balsam  solution  (i  part  of  balsam  to  3  parts  of  chloroform  or 

1  KAISER'S  GLYCERIN  JELLY. — Digest  7  Gm.  of  gelatin  in  42  Gm.  of 
water  for  two  hours  on  a  hot  water-bath ;  dissolve  i  Gm.  of  carbolic  acid  in 
49  Gm.  of  glycerin ;  mix  the  two  solutions ;  heat  on  a  water-bath,  with 
occasional  stirring,  for  fifteen  minutes,  and  finally  filter  through  glass 
wool.  The  jelly  is  warmed  slightly  to  liquefy  it  before  using. 


764  A  TEXT-BOOK  OF  BOTANY. 

benzol)  is  placed  on  a  slide  and  the  specimen  mounted.  When 
nearly  dry,  scrape  off  the  excess  of  balsam,  clean  the  slide  and 
cover-glass  with  chloroform  or  benzol,  and  ring  with  cement. 

THE  MICRO- POLARISCOPE  is  a  useful  accessory  in  conjunction 
with  the  microscope.  It  is  employed  in  the  study  of  technical 
products,  and  is  chiefly  applicable  in  the  examination  of  crystals, 
starch  grains  and  cell-walls.  A  number  of  substances,  owing  to 
certain  peculiarities  of  structure,  are  double-refracting  or  ANISO- 
TROPIC,  i.e.,  they  polarize  light.  If  the  double  refraction  is  strong 
enough  these  substances  show  a  play  of  colors.  Of  these  may 
be  mentioned  the  raphides  and  the  rosette  aggregates  of  calcium 
oxalate,  cane  sugar,  citric  acid,  benzoic  acid,  caffeine,  salicin,  aloin, 
phloroglucin,  and  the  salts  of  berberine,  strychnine,  and  atropine. 
The  acicular  crystals  which  separate  in  chloral  preparations  of 
gambir  also  show  a  play  of  colors.  Among  the  substances  which 
are  anisotropic  but  give  no  chromatic  effects  are  starch  grains, 
inulin,  mannit,  the  rhombohedra  in  catechu  and  the  various  types 
of  cell- walls.  All  substances  which  form  crystals  belonging  ta 
the  isometric  system  are  ISOTROPIC  or  single-refracting,  i.e.,  do 
not  polarize  light,  as  sodium  chloride,  the  octahedra  in  gambir, 
potassium  iodide  and  chloral. 

When  glass,  which  is  an  isotropic  compound,  is  heated  and 
suddenly  cooled  it  is  changed  into  an  anisotropic  body.  Micro- 
scopic glass  beads  formed  by  quickly  cooling  very  thin  pieces  of 
glass  show  polarization  effects  similar  to  those  of  wheat  starch 
grains.  This  has  led  to  the  supposition  that  the  polarization 
effects  produced  by  starch  grains  are  due  to  tension  rather  than 
to  a  crystalline  structure.  But  this  point  cannot  be  definitely 
settled  until  it  has  been  determined  whether  any  of  the  substances 
composing  the  layers  of  the  starch  grains  are  capable  of  crystal- 
lization. 

THE  SPECTROSCOPE  IN  MICROSCOPIC  ANALYTICAL  WORK. — To 
a  limited  extent  at  the  present  time,  and  yet  very  effectively  by 
those  who  are  competent  to  employ  it,  the  Spectroscope  is  being 
employed  in  the  examination  of  organic  coloring  substances.  This 
method  has  the  advantage  that  accurate  results  can  be  obtained  with 
small  quantities  of  material.  With  the  proper  instruments  and 
with  practice  one  may  attain  a  skill  equal  to  that  attained  in 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   765 

qualitative  and  quantitative  analytical  work.  The  Spectroscope 
can  be  used  in  checking  chemical  methods  and  also  employed 
frequently  in  the  detection  of  mixtures,  just  as  the  microscope  is 
used  where  qualitative  chemical  methods  are  not  available.  The 
Spectroscope  is  used  not  only  in  the  examination  of  single  color- 
ing principles,  but  where  there  are  mixtures,  and  whether  these 
are  in  solution,  on  fabrics,  on  paper,  etc.  So  that  for  technical 
chemists,  especially  for  those  interested  in  dyeing  and  allied  indus- 
tries, it  has  a  very  great  value. 

.  There  are  several  different  types  of  spectroscopes :  ( I )  the 
ordinary,  in  which  the  liquid  is  placed  in  a  long  glass  cell  between 
the  source  of  light  and  the  slit  of  the  spectroscope;  (2)  a  com- 
parison spectroscope,  where  an  unknown  liquid  can  be  compared 
with  that  of  a  known;  (3)  the  micro-spectroscope,  in  which  a 
spectroscope  is  attached  to  a  microscope  and  the  liquid  is  placed 
in  small  tubes. 

A  characteristic  spectrum  is  obtained  only  when  the  solution 
is  of  the  proper  dilution.  The  solutions  must  be  prepared  care- 
fully and  interfering  substances  removed  as  much  as  possible. 

( Consult :  "  Untersuchung  und  Nachweis  organischer  Farb- 
stoffe  auf  spektroskopischen  Wege,"  by  Jaroslav  Formanek  and 
Dr.  Eugen  Grandmougin,  Second  Edition.  "  Zur  Biologic  des 
Chlorophylls  Laubfarbe  und  Himmelslicht  Vergilbung  und  Etiole- 
ment,"  by  Ernst  Stahl.  "  The  Origin  and  Nature  of  Color  in 
Plants,"  Kraemer,  in  Proc.  Am.  Phil.  Soc.,  1904,  p.  259.) 

DARK  FIELD  ILLUMINATION  AND  THE  ULTRA-MICROSCOPE. — 
The  study  of  minute  particles  which  are  otherwise  not  visible 
under  the  microscope  by  direct  illumination  may  be  accomplished 
by  a  simple  contrivance  known  as  a  reflecting  condenser.  The 
principle  upon  which  this  operates  is  similar  to  when  a  pencil 
of  sunlight  enters  a  more  or  less  darkened  room,  causing  the  par- 
ticles of  dust  to  become  visible.  In  the  same  manner  the  invisible 
particles  in  a  colloidal  solution  and  the  ordinarily  structureless 
substances  in  an  animal  or  vegetable  cell  are  rendered  visible  by 
reason  of  the  contrast  between  these  particles  and  their  dark  sur- 
roundings. 

The  apparatus  consists  essentially  of  two  parts :  ( I )  a  parab- 
oloid condenser  which  has  two  reflecting  surfaces  so  as  to  bring 


766  A  TEXT-BOOK  OF  BOTANY. 

the  rays  of  light  to  a  focus  on  the  objective  and  against  a  dark 
background;  and  (2)  a  funnel  stop  objective.  The  latter  is  an 
ordinary  immersion  objective  with  the  addition  of  a  funnel  stop 
back  of  the  lenses  so  that  the  diffused  rays  only  enter  the  eye  to 
the  exclusion  of  the  direct  rays. 

An  ordinary  microscope  with  a  reflecting  condenser  and  a 
funnel  stop  objective  thus  constitutes  an  ultra-microscope.  The 
illumination  is  by  means  of  an  arc  light.  If  a  Welsbach  lamp  is 
used  it  is  necessary  to  employ  a  bull's-eye  lens  to  concentrate 
the  light  upon  the  mirror.  The  light  is  ordinarily  reflected 
through  the  condenser  from  the  plane  mirror  of  the  microscope. 
Cover-glasses  of  a  standard  thickness,  0.17  mm.,  should  be  used. 
The  space  between  the  top  of  the  condenser  and  the  microscopic 
slide  containing  the  object  must  be  rilled  with  a  layer  of  cedar 
oil  in  the  same  way  as  between  the  cover-glass  and  the  objective. 
Time  must  be  taken  to  perfectly  center  the  condenser  with  refer- 
ence to  the  objective. 

(Consult:  "  Dunkelfeldbeleuchtung  und  Ultramikroskopie," 
by  N.  Gaidukov.) 

MICRO-ANALYSIS. 

The  value  of  the  microscope  is  well  established  in  the  examina- 
tion not  only  of  the  living  plant  but  in  the  study  of  various  techni- 
cal products.  It  is  usual  to  give  greater  prominence  to  the  ANA- 
TOMICAL or  HISTOLOGICAL  method  of  study,  based  largely  upon 
the  form  of  cells  and  the  structure  and  composition  of  their  walls. 
The  study  of  cell  contents,  as  starch  grains,  calcium  oxalate> 
phyto-globulins,  and  other  definite  substances,  is  being  utilized 
very  largely  in  the  examination  of  technical  products  and  to  some 
extent  by  students  of  botany. 

A  number  of  books  have  been  published  dealing  with  the 
micro-chemistry  or  histo-chemistry  of  some  of  these  substances. 
For  the  most  part  the  study  of  microscopic  crystals  has  been  of 
a  very  general  nature,  in  that  statements  are  given  regarding 
the  general  shape  of  the  crystals  or  their  aggregates  and  their 
behavior  with  certain  test  solutions.  The  time  has  come  when 
the  study  of  the  crystalline  substances  found  in  plants  requires, 
if  any  real  progress  is  to  be  made  in  this  direction,  that  the 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   767 

CRYSTALLOGRAPHIC  METHOD  of  examination  be  utilized.  This 
method  originated  in  the  examination  of  thin  sections  of  rocks 
and  it  has  been  possible  by  this  study  to*  identify  the  numerous 
rock-forming  mineral  species.  In  those  species  which  are  mixed 
crystals,  i.e.,  made  up  of  isomorphous  mixtures  of  two  or  more 
components,  it  has  been  possible  to  determine  with  some  accuracy 
their  composition  simply  by  their  optical  properties,  as  for  exam- 


FIG.  420.    Codeine:  x-shaped  skeleton  crystals  from  TO  per  cent,  alcoholic  solution. 

pie  the  feldspars.  Furthermore,  it  has  been  possible  to  draw 
conclusions  as  to  the  ultimate  composition  of  rocks  and  the 
conditions  under  which  they  were  formed. 

The  value  and  possibilities  of  the  employment  of  the  crystal- 
lographic  method  in  biological  studies  is  well  exemplified  in  the 
recent  work  of  Reichert  and  Brown,  "  The  Crystallography  of 
the  Hemoglobins."  By  special  means  individual  crystals  of  the 
hemoglobins  were  obtained  and  by  purely  crystallographic 
methods,  including  a  study  of  the  forms  and  optical  properties 
of  such  crystals,  the  hemoglobins  of  the  200  species  of  animals 


768 


A  TEXT-BOOK  OF  BOTANY. 


studied  were  differentiated  in  a  manner  that  could  not  have  been 
accomplished  by  chemical  analysis  or  other  methods  of  procedure. 
A  careful  study  of  much  that  has  been  written,  and  especially 
of  the  illustrations  that  have  been  made,  of  micro-crystals  in 
plants  and  drugs,  shows  that  erroneous  conclusions  may  be  easily 
drawn  from  the  general  appearance  of  crystalline  precipitates  or 
aggregates  of  crystals  that  are  formed.  For  instance,  Vogl  has 


FIG.  421.  Cubebin:  orthorhombic  crystals  from  Prollius'  solution,  showing  various 
types  of  twinning  (a,  b,  c);  d,  amorphous  material  in  the  form  of  oi.lv  drops  (under-cooled 
liquid);  e,  this  amorphous  material  crystallizing  in  aggregates. 

shown  that  the  sphero-crystals,  found  in  the  glandular  hairs 
of  Mentha  piperita  and  considered  by  some  to  be  menthol,  are 
found  in  leaves  of  many  of  the  Labiatae.  Again,  very  many  sub- 
stances produce  aggregate  groups  which  closely  resemble  each 
other,  as  of  citric  acid,  cocaine  hydrochloride,  etc. 

In  regard  to  the  value  of  the  crystallographic  method  we 
quote  the  following  paragraph  from  Brown  (loc.  cit.)  :  "When 
a  chemical  compound  solidifies  from  fusion,  solution  or  vapor 
under  conditions  which  are  favorable  to  the  development  of 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   769 

individuals,  its  particles  tend  to  arrange  themselves  in  regular 
order,  so  that  a  definite  structure  is  produced.  The  external 
form  of  the  individuals  is  also  regular,  being  bounded  by  planes 
in  definite  relation  to  each  other  so  that  polyhedral  solids  are 
produced  which  are  called  CRYSTALS.  The  regular  arrangement 
of  the  atoms  among  themselves,  and  of  the  molecules  which 


FIG.  422.     Strychnine  sulphate:  tetragonal  crystals  in  polarized  light,  showing  side  aspect. 

they  build  up,  is  so  characteristic  of  substances  of  definite  com- 
position that  the  crystalline  condition  of  dead  matter  is  the  normal 
condition.  Differences  in  chemical  constitution  are  accompanied 
by  differences  of  physical  structure,  and  the  crystallographic  test 
of  differences  of  chemical  constitution  is  recognized  as  the  most 
delicate  test  of  such  differences." 
49 


770  A  TEXT-BOOK  OF  BOTANY. 

It  is  apparent  that,  apart  from  their  solubility,  color  reactions, 
behavior  towards  reagents,  etc.,  the  substances  with  which  we 
are  dealing  should  be  prepared  in  such  a  manner  that  isolated 
crystals  are  formed  and  not  aggregates  or  groups.  These  isolated 
crystals  can  then  be  studied  independently.  The  reason  why 


FIG.  423.     Hydrastine:  large,  nearly  equidimensional  orthorhombic  crystals  from  alcoholic 

solution. 

aggregates  are  formed  is  because  the  crystals  are  permitted  to 
grow  too  rapidly  on  the  slide.  This  is  usually  the  case  in  the 
usual  method  of  procedure  in  securing  crystals,  i.e.,  by  adding 
a  drop  of  a  solution  to  the  slide,  and  then  allowing  it  to  evaporate 
spontaneously,  under  ordinary  conditions.  If,  on  the  other  hand, 
the  rate  of  evaporation  is  lessened  so  that  there  is  a  slowing  down 
of  the  growth  of  the  crystals,  individuals  may  be  obtained  of 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   771 

almost  any  size  desired.  And  it  will  be  found  that  these  isolated 
crystals  may  be  quite  as  easily  prepared  as  the  aggregates  which 
seem  so  characteristic  to  the  average  student.  Special  methods, 
however,  may  be  necessary  to  obtain  such  isolated  crystals.  For 
instance,  single  crystals  of  menthol  (Fig.  126)  are  obtained  by 


FIG.  424.     Pipeline:  monoclinic  crystals,  mostly  on  the  clinopinacoid,  showing  the  oblique 
terminations,  obtained  from  hot  alcoholic  solution. 

means  of  sublimation  rather  than  from  solutions.  Cumarin 
crystals  are  easily  obtained  by  controlling  the  temperature  of  the 
melted  mass,  etc. 

The  interest  in  these  crystalline  substances  is  becoming  greater 
as  foods  and  drugs  and  technical  products  are  subject  to  stand- 
ards of  purity.  Most  of  the  crystalline  constituents  common  to 


'772  A  TEXT-BOOK  OF  BOTANY. 

plant  products  are  usually  said  to  be  calcium  oxalate.  This  sub- 
stance is  insoluble  in  water,  alcohol,  and  acetic  acid,  soluble  in 
the  mineral  acids  and  occurs  usually  in  definite  crystals.  These 
crystals  are  rather  easily  studied  in  Iris,  Quillaja,  etc.  (see  page 
186).  They  are  found  to  crystallize  either  in  the  tetragonal  or 
monoclinic  systems,  sphenoids  of  the  latter  being  present  in 
Belladonna  (see  pages  183-192). 

Some  substances  occur  in  a  crystalline  form  even  upon  the 
commercial  product,  as  vanillin  upon  vanilla  pods  and  cumarin 
upon  tonka  seeds;  or  crystals  may  be  found  in  special  cells,  as 
piperine  (Fig.  424)  in  Piper  album  and  Piper  nigrum.  In  alco- 
holic material,  particularly  of  the  Composite,  characteristic  sphere- 
crystals  are  found,  as  in  inula  (see  pages  150-154).  Sometimes 
similar  sphero-crystals  are  observed  upon  soaking  the  drug  of 
commerce  in  water  and  then  adding  alcohol,  as  in  Scilla.  Again, 
crystalline  substances  separate  upon  the  addition  of  mineral  acids, 
as  when  nitric  acid  or  sulphuric  acid  is  added  to  sections  of 
Hydrastis  (Fig.  95).  Again,  upon  dissolving  the  product  either 
in  water,  as  with  catechu,  or  in  solutions  of  chloral,  as  with 
gambir,  a  crystalline  residue  remains.  Finally,  upon  extracting 
the  dried  plant  with  suitable  solvents,  as  Prollius'  solution,  and 
evaporating  the  solvent,  characteristic  crystals  separate,  as  with 
coca,  hydrastis,  nux-vomica,  cinchona,  cola,  guarana,  etc. ;  or 
distinct  crystalline  precipitates  may  be  obtained  upon  the  addition 
of  special  reagents,  as  palladous  chloride  to  solutions  containing 
cocaine  hydrochloride  (Fig.  97),  or  gold  chloride  to  solutions 
containing  caffeine  (Fig.  96) .  Attention  has  already  been  directed 
to  the  fact  (pages  173-^176)  that  quite  a  number  of  plant  principles 
are  capable  of  being  sublimed. 

For  some  time  past,  in  the  study  of  certain  of  the  cryptogams, 
as  bacteria,  yeasts,  and  fungi,  there  has  been  a  disposition  to  rely 
upon  physiological  rather  than  morphological  characters,  this 
being  due  not  only  to  the  fact  that  these  are  more  constant  and 
characteristic  in  these  organisms,  but  also  to-  the  fact  that  distinct 
morphological  characters  are  entirely  wanting  in  some  cases. 
While  the  necessity  for  this  additional  study  in  the  higher  plants 
is  not  so  apparent  on  account  of  the  presence  of  well-defined 
morphological  characters,  still  the  value  of  physiological  marks 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   773 

as  one  of  the  bases  of  classification  is  coming  to  be  recognized. 
The  best  illustration  of  this  is  to  be  found  in  the  monograph 
of  the  genus  Eucalyptus  by  Baker  and  Smith,4  in  which  they 
have  utilized  the  chemical  properties  and  physical  characters  of 
the  oils,  coloring  principles,  tannins,  etc.,  in  establishing  differ- 
ences of  affinities  or  species.  There  is  a  growing  tendency  on  the 
part  of  investigators  to  study  micro-chemically  some  of  the  char- 
acteristic plant  constituents,  as  alkaloids,  etc.  As  a  rule,  how- 
ever, the  descriptions  are  superficial  and  the  identification  is  by 
means  of  color  reactions.  No  real  scientific  progress  will  be 
made  until  the  botanist  employs  the  petrographical  microscope 
and  is  fairly  well  grounded  in  the  principles  of  physical  and 
chemical  crystallography.  The  work  is  by  no  means  so  simple 
as  in  ordinary  microscopic  work,  but  when  the  principles  governing 
the  optical  study  of  crystals  are  mastered,  the  study  will  appeal  to 
botanists  not  only  as  a  fertile  field  for  research  but  also  as  a 
subject  of  importance  in  both  morphological  and  taxonomic  work. 

The  study  of  microscopic  crystals  is  accomplished  by  means 
of  the  petrographical  microscope.  Brown  (loc.  cit.)  has  stated 
succinctly  the  nature  and  use  of  this  instrument : 

"  The  necessity  of  studying  small  crystals,  .  .  .  has  re- 
sulted in  the  evolution  of  a  form  of  microscope  which  is  at  once 
a  goniometer,  a  polariscope,  and  an  instrument  for  measuring 
optic  axial  angles — in  short,  for  determining  the  physical  crys- 
tallographic  constants  of  small  crystals.  .  .  .  The  polari- 
scope portion  of  the  petrographical  microscope  enables  the  ob- 
server to  determine  the  position  and  relative  value  of  the  elasticity 
axes  of  crystals,  to  observe  the  position  of  the  optic  axes,  and 
to  determine  their  inclination  to  each  other  and  to  the  elasticity 
axes.  From  these  data  the  optical  character  of  the  crystal  is 
determined.  These  OPTICAL  REACTIONS  may  be  studied  by  this 
instrument  with  as  much  ease,  and  in  general  with  as  much 
accuracy,  as  with  the  larger  and  better  graduated  polariscope; 
and  the  data  thus  obtained  are  quite  as  accurate  in  most  cases 
as  those  obtained  by  the  use  of  the  larger  instruments.  The. 
use  of  the  special  eye-pieces  arranged  with  artificial  twins  of 
calcite  or  quartz  enables  the  observer  to  determine  the  extinction 


774  A  TEXT-BOOK  OF  BOTANY. 

angles  of  the  crystals  with  as  much  accuracy  as  can  be  done  with 
any  form  of  polariscope. 

"  From  such  observations  made  with  the  aid  of  this  form  of 
microscope  the  following  constants  may  be  determined: 

"  ( i )  The  plane  angles  of  the  crystals,  in  most  cases  the 
interfacial  angles,  giving  the  data  from  which  the  axial  ratios  are 
computed—in  other  words,  the  morphological  constants  of  single 
crystals. 

"  (2.)  The  relation  of  the  composite  crystals  or  twins  to  each 
other,  their  angles,  and  the  position  of  the  twin  plane,  twin  axis, 
composition  plane,  and  other  constants  of  the  twin  crystals. 

"  (3)  The  pleochroism  of  the  crystals,  the  character  of  the 
colors  of  the  light  vibrating  parallel  to  the  elasticity  axes  in 
the  crystals.  This  is  effected  by  the  use  of  the  single  polarizing 
prism  below  the  stage.  By  analyzing  this  light  with  the  micro- 
spectroscope  the  differences  of  tint  and  color  may  be  given 
quantitative  values  in  wave  lengths. 

"  (4)  The  position  and  relative  values  of  the  light  elasticity 
axes  in  the  crystals,  upon  which  depend  the  angles  of  extinction 
of  the  crystals,  measured  from  certain  crystallographic  axes  or 
planes  or  edges.  In  uniaxial  crystals  (tetragonal  and  hexagonal 
systems)  there  are  two  such  elasticity  axes — the  ordinary  ray  des- 
ignated as  w,  and  the  extraordinary  ray,  designated  as  e.  Either 
one  of  these  may  be  the  axis  o*f  greater  or  less  elasticity ;  and 
according  as  the  extraordinary  ray  is  the  axis  of  less  elasticity 
or  of  greater  elasticity  the  crystal  is  called  optically  POSITIVE 
or  optically  NEGATIVE.  In  biaxial  crystals  (orthorhombic,  mono- 
clinic  and  triclinic  systems)  there  are  three  elasticity  axes  at 
right  angles  to  each  other,  and  these  are  designated  as  fl,  the 
axis  of  greatest  elasticity;  J),  the  axis  of  mean  elasticity;  and 
(,  the  axis  of  least  elasticity.1 

"  (5)  The  position  and  angle  of  inclination  of  the  optic  axes 
or  lines  of  single  refraction  through  the  crystals.  These  always 
lie  in  the  plane  of  the  elasticity  axes  &  and  t  and  the  angles 
between  the  optic  axes  are  bisected  by  the  axes  &  and  C.  Accord- 
Elasticity  in  the  optical  sense  is  the  reciprocal* of  refractive  index; 
.hence  a,  b,  t,  are  the  axes  of  least,  mean  and  greatest  refractive  index. 


MICROSCOPIC  TECHNIQUE  AND  REAGENTS.   775 

ing  as  to  whether  t  or  a  is  the  axis  bisecting  the  acute  angle,  the 
ACUTE  BISECTRIX,  Bxa,  the  crystal  is  called  optically  POSITIVE 
or  optically  NEGATIVE.  Thus  if  Bxa  -  t,  the  optical  -character  is 
POSITIVE.  The  apparent  angle  between  the  optic  axes  is  deter- 
mined by  means  of  an  eye-piece  micrometer  in  an  observation  of 
the  interference  figure,  looking  along  the  acute  bisectrix  of  the 
optic  axes,  and  this  angle  is  designated  as  2.E.  The  character 
of  the  double  refraction  may  be  determined  by  this  angle." 

It  is  not  possible  in  this  work  even  to  attempt  to  treat  of  the 
principles  underlying  the  study  of  physical  crystallography.  The 
study  is  one  requiring  special  laboratory  instruction.  Of  the 
excellent  works  which  the  student  will  find  useful  the  following 
may  be  mentioned : 

P.  GROTH  :  Physikalische  Krystallographie,  4th  Ed.,  1905. 

THEODOR  LIEBISCH  :    Grundriss  der  Physikalischen  Krystallographie,  1896. 

HENRY  A.  MIERS:  Mineralogy,  1902.     In  this  work  will  be  found  several 

excellent  chapters  dealing  with  the  principles  of  the  measurement  of 

crystals  and  the  study  of  their  optical  properties. 
ROSENBUSCH  AND  WuLFiNG :   Mikroskopische  Physiographic  der  Mineralen 

und  Gesteine. 
P.  GROTH  :    An  Introduction  to  Chemical  Crystallography.     Translated  by 

Hugh  Marshall,  1906. 

In  the  Zeitschrift  fiir  Krystallographie  will  be  found  refer- 
ences to  the  crystallographic  studies  which  have  been  made  upon 
some  of  the  important  plant  constituents,  but  as  these  studies 
were  mostly  made  upon  relatively  large  crystals,  which  could  be 
measured  and  examined  by  means  of  the  goniometer,  these 
observations  must  be  interpreted  and  applied  to  crystals  which 
are  formed  upon  microscopic  slides. 

A  rather  large  number  of  substances  have  been  examined  and 
only  a  few  of  the  more  important  are  included  at  this  time. 
While  drawings  might  have  been  made  to  illustrate  the  form  of 
crystals  and  optical  orientations,  it  was  deemed  advisable  to  use 
some  of  the  photo-micrographs  made  by  the  author.  The  four- 
color  plate  (Figs.  99,  100)  is  introduced  to  show  the  chromatic 
effects  observed  by  using  crossed  nicols.  The  plate  illustrates 
salicin  and  cocaine  hydrochloride  and  is  a  nearly  exact  reproduc- 
tion of  the  effects  obtained  with  the  micro-polariscope,  the  electros 


776  A  TEXT-BOOK  OF  BOTANY. 

having  been  made  from  Lumiere  autochrome  plates,  using  direct 
sunlight. 

The  method  of  obtaining  the  crystals  was  rather  simple.  The 
solvents  used  were  distilled  water,  alcohol,  ether,  chloroform 
and  a  mixture  of  chloroform  and  alcohol.  To  a  weighed  amount 
of  the  substance  was  added  a  sufficient  quantity  of  solvent  to 
give  a  saturated  solution.  A  drop  of  this  was  added  to  a  slide 
which  was  covered  either  with  a  bell-jar  or  the  cover  of  a  Petri 
dish.  If  the  crystals  formed  too  rapidly,  giving  rise  to  crystal 
aggregates,  more  dilute  solutions  were  made  from  the  original 
solution  until  single  crystals  were  obtained  therefrom.  In  some 
instances,  as  with  physostigmine  salicylate,  where  the  edges  of 
the  crystal  are  likely  to  be  re-dissolved,  the  slides  were  finally 
dried  in  a  desiccator  over  sulphuric  acid.  With  caffeine  gold 
chloride,  the  best  crystals  were  obtained  when  the  solutions  were 
relatively  weak.  Again,  it  was  found  that  after  crystals  were 
mounted  in  balsam,  as  cocaine  hydrochloride,  caffeine  gold  chlo-i 
ride,  etc.,  the  isolated  crystals  grew  considerably  in  size  at' 
the  expense  of  amorphous  material.  A  rather  unique  instance 
of  growth  of  large  crystals  was  with  menthol  when  the  slide  con- 
taining the  silky  aggregates  was  covered  with  another  slide. 
Finally  it  should  be  stated  that  some  patience  and  experience  are 
necessary  to  obtain  satisfactory  crystals. 

WORKS  OF  REFERENCE. 

Principles  of  Microscopy.    By  A.  E.  Wright. 

Das  Mikroskop.     By  Leopold  Dippel. 

Anleitung  zur  Mikrochemischen  Analyse.     By  H.  Behrens. 

Die  Botanische  Mikrotechnik.    By  A.  Zimmermann. 

Methods  in  Plant  Histology.     By  Charles  J.  Chamberlain, 

Elements  of  Drawing.     By  John  Ruskin. 

For  Drawing  of  Crystals,  consult  "  Crystallography  and  Practical  Crystal 

Measurement,"   by   A.   E.   H.   Tutton. 
Physical  Optics      By  Robert  W.  Wood. 


INDEX. 


Abelmoschus,  434 
Abies,  119,  213,  434 
Abnormal     root     structure, 
319 

stem  structure,  344 
Abortive,  391 
Abrin,  198,  575 
Abroma,  615 
Abrotanum,  434 
Abrus,  434.  575 
Absinthe,  719 
Absinthin,  719 
Absinthium,  434,  719 
Abuta,  539 
Abutilon,  610,  611 
Acacia,  434,  567,  569,  575 
Acajou  gum,  599 
Acanthaceae,  694 
Acanthus  family,  694 
Accumbent,  426 
Acer,  434,  602 
Aceraceae,  602 
Acetaldehyde,  234 
Achene,  410 
Achillea,  172,  434,  720 
Achilleine,  172 
Achras,  659 
Achyranthes,  528 
Acid  abietic,  237 

acetic,  234 

amido-succinamic,  168 

amino-acetic,  192 

antirrhinic,  691 

arabic,  222 

arachidic,  212 

behenic,  212 

benzoic,  234 

capric,  212 

caproic,  212 

caprylic,  212 

carthamic,  720 

cerasic,  223 

chaulmoogric,  214 

chebulinic,  633 

chromic,  756 

cinnamic,  234,  572 

formic,  234,  287 

gallic,  599 

gurjunic,  621 

gynocardic,  623 

hederic,  636 

hydrocyanic,  198,  235 

hypogaeic,  213 

isovaleric,  234 

japanic,  213 

kinic,  655 


Acid,  lactic,  zymase,  245 

lauric,  212 

lichen,  72 

lignoceric,  212 

linoleic,  213 

lycopodic,  213 

magenta,  182 

methysticinic,  177 

myristic,  212 

oleic,  213 

palmitic,  212 

pectinic,  243 

phosphomolybdic,  164 

phosphoric,  214 

picric,  165,  756 

picric-sulphuric,   as  fixing 
agent,  756 

pipitzahoic,  723 

protocatechuic,  204 

rapic,  213 

resinolic,  237 

ricinoleic,  213 

salicylic,  234 

stearic,  212 

succino-abietic,  237 

sulphuric,  in  germination, 
731 

tiglic,  213 

yellow  A.  T.,  182 
Aconite,  434,  533,  534 
Aconitum,  tubers  of,  328 
Acorn-cups,  tannin  in,  206 
Acorus,  434,  479 
Acre,  434 
Acris,  434 
Actaea,  434,  537 
Actinomorphic,  393 
Acubin,  696 
Acuminate,  355,  434 
Acuminatus-a-um,  434 
Acute,  354 

Acutifolius-a-um,  434 
Adansonia,  612 
Adder's  tongue,  458 
Adderwort,  438 
Adhatoda,  696 
Adhesion,  390 
Adiantum,  88,  434 
Adlumina,  550 
Adnate,  381 
Adnation,  390 
Adonis,  434.  537 
Advena,  434 
Adventitious  root,  301 
^Ecidiospores,  69 
/Ecidium,  69 


A6gle.  434 
Aerial  root,  306 
Aerobes,  252 
^Esculin,  169,  602 
^Esculis,  602 

tannin  in,  206 
^Estivalis,  434 
African  ammoniac,  639 
Afzelia,  575 
Agar-agar,  34 
Agaric,  63,  64,  456 

surgeon's,  65 
Agaricaceae,  59 
Agaricus,  434 

campestris,  59 
protein  in,  200 

muscarius,  155 
Agave,  434.  489 

constituents  of,  492 

fiber,  269 
Agavose,  155 
Agglutins,  198 
Aggregatae,  707 
Aglykone,  169,  170 
Agrimonia,  434 
Agropyron,  434,  468 
Agrostemma,  172,  426,  434 
Ailanthus,  434,  586 

family,  585 
Air-bubbles,  752 

method  of  detection,  752 
Air  plants,  480 
Aizoaceae,  528 
Ajowan  oil,  643 
Ajuga,  434 

Akene  (see  Achene),  410 
Albizzia.  575,  435 
Albumins,  194,  195 
Albus-a-um,  435 
Alchemilla,  435 
Alcoholase,  245 
Alcohol,  benzyl,  233 

camphyl,  233 

ceryl,  214 

cinnamic,  233 

ethyl,  233 

melissyl,  214 

methyl,  233 
Aldehyde,  234 

cinnamic,  544 

salicylic,  564 
Alder,  435,  510 

buckthorn,  604 
Aletris,  435,  480 
Aleurites,  592 

oil  in,  213 

777 


INDEX. 


Aleurone,  grains,  193 
Alfa,  472 
Alfalfa,  577 
Algae,  7,  435 

blue-green,  8 

characteristic,  16 

classes,  17 

economic  uses  of,  40 

of  Red  Sea,  8 

of  Yellowstone  Park,  8 

polluting  water,  8 

used  as  food,  40 

used  in  medicine,  40 
Alga-fungi,  42 
Alisma,  466 
Alismaceae,  466 
Alizarin,  179.  7O3 

preparation  of,  704 
Alkaloids,  159 

chemical   classification, 
1 66 

effect  of  climate  on,  165 

families  yielding,  165 

from  cultivated  and  wild 
plants,  739 

functions  of,  172 

microchemistry  of,  160 

origin  of,  160 

properties  of,  163 

reagents  for,  163 
Alkanet,  670 
Alkanna,  670 
Alkannin,  670 
Allisin,  489 
Allium,  435,  485,  489 

vascular  bundle  of,  309 
Allspice,  455 

wild,  438 
Almond,  435 

emulsin,  243 

oil  in,  213 
Alnus,  435.  5io 

glandular  hairs  in,  230 
Aloe,  435 

species  of,  487 

wood,  628 
Alpinia,  494.  651 
Alsine,  435.  53 1 
Alstonia,  435 
Alteration  in  forms  of  plants, 

332 
Alternation    of    generation, 

78,  86 

Althaea,  435,  609,  6n 
Alum  root,  447,  556 
Alyssum,  435 
Amandin,  195 
Amanita,  60-65 
Amarantaceae,  528 
Amaranth,  435 
Amaranthus,  435,  528 
Amarus-a-um,  435 
Amaryllidaceae,  489 
Amaryllis,  435,  492 
Amaryllus  family,  489 


Amber,  119,  237 

fossil,  119 

seed,  6ll 

Ambrosia,  435,  726 
Ambrosiaceae,  712 
Ambrosioides,  435 
Amelanchier,  562 
Aments,  508 
American  aloe,  434 

copal.  574 

kino,  569,  571 

linden,  608 

pennyroyal,  676 

senna,  360 

Americanus-a-um,  435 
Amino-acid,  167 
Ammanni,  435 
Ammoniac,  639 

African,  639 

plant,  444 
Ammoniacum,  435 
Amomum,  435,  494 
Amorpha,  435,  574 
Amygdalin,  169,  170 
Amygdalus.  435 
Amylo-dextrin,  145 
Amylo-pectinase,  242 
Amylose,  144,  242 
Amylum,  435 
Amyris,  585 
Anabasis,  527 
Anacardiaceae,  595 
Anacardium,  435,  596,  599 
Anacyclus,  435  714 
Anaerobes,  252 
Anagallis,  436 
Anagyris,  575 
Analysis,  micro,  776 
Anamirta,  436,  539 
Ananas,  436,  480 
Anatomical     differences     in 

leaves,  370 
Anatomy,  i 
Anatropous,  379 
Andira,  436 
Andrcecium,  381 
Andromedotoxin,  648 
Andropogon,  436,  467,  472 
Anemone,  359,  436,  535,  537 
Anemonol,  537 
Anemonon,  537 
Anemophilous  flowers,  399 
Anethol,  234,  643 
Anethum,  436,  643 
Angelica,  436 

American,  643 

European,  643 

purple  stemmed,  643 

wild,  643 
Angiosperms,  119 

classification  of,  463 

development  of,  120 

economic    importance    of, 
128 

flowers  of,  375 


Angostura,  436,  443,  585 
Angustifolius-a-um,  436 
Anhalonidine,  625 
Anhalonine,  625 
Anhalonium,  625 
Aniline     blue,     as     staining 

agent,  757 
Anime,  586 
Anise,  436,  448,  639 

Japanese  star,  540 

protein  in,  200 

star,  448 
Anise-scented       golden-rod, 

722 

Anisomeria,  528 
Anisum,  436,  448,  639 
Annatto,  621 
Annual  herbs,  330 

rings,  343 
Annular,  273 
Annulus  or  ring,  61 
Annuus-a-um,  436 
Anogra,  436 
Anona,  542 
Anonaceae,  541 
Anthelminticus-a-um,  436 
Anthemis,  436,  713 
Anther,  379 

appendages  of,  381 
Antheridium,  5 
Antherozoid,  5 
Anthoceros,  83 
Anthocyanin,  209,  210 

origin  of,  180 
Anthophylli,  631 
Anthotaxy,  393 
Anthoxanthum,  436,  472 
Anthracene,  170 

derivatives,  179 
Antidesma,  594 
Antirrhinic  acid,  691 
Aparine,  436 
Apeiba,  609 
Apex  of  leaf,  354 
Apiin,  169,  170 
Apiol,  234,  643 
Apiose,  169 
Aplastic,  172 
Apocarpous,  376 
Apocynaceae,  574,  664 
Apocynum,  386,  436,  664 

fruit,  412 

seed,  429 
Apostasieae,  496 
Apothecia,  73 
Appendages  of  anther,  381 
Apple,  457,  562 

cedar,  115 

earth,  440 

may,  538 

protein  in,  199 

rose,  632 

rust,  115 

star,  441,  659 

sugar  in,  156 


INDEX. 


779 


Apricot,  562,  620 

oil  in,  213 

protein  in,  199 

sugar  in,  156 
Aquaticus-a-um,  436 
Aquifoliaceae,  600 
Aquifolium,  436 
Aquilaria,  628 
Aquilegia,  536 
Arabicus-a-um,  436 
Arabin,  222 
Araceae,  475,  478 
Arachis,  401,  576 
Arachnoidiscus,  35 
Aragallus,  574 
Arales,  475 
Aralia,  436,  636,  637 
Araliaceae,  636 
Araroba,  436 

tree,  462 
Arbor,  460 

vitae,  118 
Arbutin,    169,    170,    174, 

176 

Arbutus,  trailing,  644,  649 
Archegoniates,  75 
Archegonium,  75 
Archesporium,  79,  124 
Archichlamydeae,  504 
Arctium,  436,  715,  717 
Arctostaphylos,     174,     436, 

644.  651 
Areca,  436,  473 
Arecaidine,  474 
Arecaine,  474 
Arecoline,  473 
Arethusa,  502 
Argania,  659    ' 
Argemone,  436,  547 
Arginin,  253 
Argithamnia,  436,  594 
Arillode,  427 
Arillus,  427 

Arisaema,  436,  477.  480 
Aristolochia,  436,  519,  521 
Aristolochiales,  519 
Aristotelia,  609 
Arnica,  437,  715 

pollen  of,  404 
Arnotta,  621 
Aromaticus-a-um,  437 
Aros,  437 
Arrow-head,  466 
Arrow-poison,  516,  575.  593, 

633,  662 
Arrow  root,  462 

Maranta,  496 

soft-leaved,  706 

starch,  496 
Arrow  wood,  705 

maple-leaved,  705 
soft-leaved,  706 
Artemisia,  437,  719 

hairs  of,  285 
Artemisiaefolius-a-um,  437 


Arthrospore,  12 
Artichoke,  ferment  in,  244 

globe,  726 

Jerusalem,  725 
Artificial  coloring  of  flowers, 

182 

Artocarpus,  437,  516 
Arum,  437,  478 
Arundinaceus-a-um,  437 
Arvensis-e,  437 
Asafoetida,  445,  639 
Asagraea,  437 
Asarone,  520 
Asarum,  365,  437,  520 
Asci,  47 

Asclepiadaceae,  574,  668 
Asclepias,  437.  667,  668 
Ascomycetes,  47 
Ascophyllum,  30 
Ascus,  47 
Asexual  generation,  298 

spore,  298 
Ash,  446 

mountain,  562 

prickly,  462 

white,  661 

wild  mountain,  454 
Asimina,  437,  541 
Asparagine,  167,  253,  725 
Asparagus,  437,  485,  489 

protein  in,  199 

sugar  in,  156 
Aspen,  456 
Aspergillus,  49 
.    emulsin,  243 
Asperula,  437 
Aspidium,  437 
Aspidosperma,  437,  667 
Asplenium,  437 
Assimilation  root,  306 

shoot,  299 
Aster,  712,  726 
Astragalus,  437,  569,  574 

gum  in,  218 

Athamanticus-a-um,  437 
Atmospheric  nitrogen,   fixa- 
tion of,  307 
Atriplex,  437.  52? 
Atropa,  437,  683,  684 

fruit,  412 
Atropous,  379 
Atropurpureus-a-um,  437 
Attar  of  rose,  564 
Aucuba,  643 
Aucubin,  643 
Aurantiamarin,  585 
Aurantium,  437 
Auric  chloride,  165 
Australis-e,  437 
Autumnalis-e,  437 
Auxochrome,  179 
Auxospores,  37 
Avena,  437,  467 

structure  of,  423 
Avenalin,  195 


Avens,  446 

Avocado,  455 

Ax-seed,  442 

Azalea,    glandular   hairs   in, 

230 
purple,  646 

Baccaurea,  594 
Baccharis,  437,  723 
Baccifer-a-um,  437 
Bacillus,  14 

hay,  13 

subtilis,  13 

typhosus,     destroyer     of, 

655 
Bacteria,  12 

aerobic,  12 

anaerobic,  12 

classes  of,  13 

sulphur,  14 
Bacterium,  14 
Balanophora,  519 
Balanophoraceae,  519 
Balata,  gum,  659 
Balatium,  241 
Ballota,  437 
Balm,  452 

of  Gilead,  508 

sweet,  679 
Balsam,  225 

Canada,  as  mounting  me- 
dium, 757 

gurjun.  621 

.Maiacaibo,  572 

mounts,  763 

of  fir,  118 

of  the  gardens,  604 

of  Tolu,  572 

Oregon,  119 

poplar,  508 

Sindor,  621 

tree,  461 

Balsamifer-a-um,  438 
Balsaminaceas,  604 
Balsams,  236 
Balsamum,  438 
Bambusa,  466 
Banana,  496 

protein  in,  199 

sugar  in,  156 
Baneberry,  434,  537 
Banskia,  518 
Baobab,  612 

Baptisia,  438,  567,  573.  575 
Baptisin,  169 
Barbaloin,  169 
Barbarea,  438 
Barberry,  438 

family,  537 
Barbiera,  575 
Barium  salts,  575 
Bark,  317 
Barley,  448 

lecithin  in,  214 

protein  in,  199 


78o 


INDEX. 


Barley,  starch  in,  148 

sugar  in,  156 
Barosma,  438,  583 
Barringtonia,  629 
Base  of  leaf,  356 
Basidiomycetes,  56 
Basil,  sweet,  679 
Bassia,  659 
Bassorin,  223 
Basswood,  609 
Bastard  cedar,  580 

santal,  580 
Bauhinia,  575 
Bayberry,  212,  508 
Bay  oil,  632 

rum,  632 

Beale's  carmine  solution,  760 
Bean,  576 

buck,  452 

garden,  576 

Indian,  440 

Japanese  soy,  576 

kidney,  455 

lima,  199 

pichury,  453 

protein  in,  199 

Sacred,  453 

sea,  575 

Bearberry,  436,  461,  651 
Beard  grass,  436 
Bearwort,  452 
Beauty,  meadow,  634 
Bebeeru,  453,  546 
Bedstraw,  446,  697,  704 

yellow,  704 
Beeberine,  546 
Beech,  445,  510 

American,  512 

drops,  696 
false,  644 

nut,  protein  in,  199 

purple,  178 

red,  512 

Beer  manufacture,  515 
Beet,  438,  527 

garden,  protein  in,   199 
sugar  in,  156 

sugar,  527 

proteins  in,  199 
sugar  in,  156 
Beggiatoa,  14 
Begonia,  624 

hairs  in,  282 
Begoniaceae,  624 
Belladonna,  438,  683,  740 

hairs  of,  284 

lily,  435 

root,  cross  section  of,  318 
Bell-flower  family,  710 
Bellwort,  485 
Benedictus-a-um,  438 
Bengal  quince,  434 
Benne  oil,  691 
Benzaldehyde,  234 
Benzoinum,  438,  660 


Benzo-quinhydrone,  179 
Benzoquinone,  179 
Benz-pyrrol,  180 
Berberidaceas,  537 
Berberine,  162,  180 
Berberis,  438,  537 
Bergamia,  584 
Bergamot,  679 

oil,  584 

wild,  679 
Berry,  410 

partridge,  452 
Bertholletia,  629 
Beta,  438,  527 

stomata  on  leaves,  367 
Betel,  508 

leaves,  506 

nut,  436,  473 
palm,  476 
Betonica,  438 
Betony,  438 
Betula,  438,  510 

cross-section  of  wood,  346 
Betulaceae,  510 
Betulase,  243 
Betulinus-a-um,  438 
Bezoars,  vegetable,  577 
Bhang,  516 
Bicollateral     mestome 

strands,  341 
Bicuculla,  550,  551 
Bidens,  438 
Biennial  herb,  330 
Biennis-e,  438 
Bifacial  leaves,  349,  366 
Biflorus-a-um,  438 
Bigardia  oil,  584 
Bignonia,  438 
Bignoniaceae,  691 
Bilabiate,  386 
Bilberry,  654,  655 
Bind  weed,  442 
Birch,  438,  510 

family,  510 

white,      cross-section      of 

wood,  346 
Bird  food,  696 
Bird-lime,  518 
Birthroot,  461 
Birthwort,  436 

family,  519 
Bisectrix,  775 
Bishop's  cap,  452 
Bismarck  brown,  as  staining 

agent,  757 
Bistorta,  438,  527 
Bitter  sweet,  444,  684 
Bixa,  621          4 
Bixaceae,  621 
Bixin,  622 
Blackberry,  458 

bush,  563 

low,  563 

sand,  563 

sugar  in,  156 


Black  catechu,  569 

haw,  462,  704 

hellebore,  537 
Bladder-wrack,  28 
Blade,  348 
Blakea,  634 
Blazing  star,  449 
Blights,  44 
Blinding  tree,  592 
Blood  orange,  584 

root,  458,  547 

Blueberry,     cultivation     of. 
656 

dwarf,  653 

early  sweet,  653 

high  bush,  655 

low,  654 

low-bush,  655 
Blue  flag,  larger,  492 

indigo,  574 
Bluets,  448,  697 
Bocconia,  550 
Boehmeria,  438,  517 

fibers  in,  269 
Bcerhavia,  528 

hairs  in,  282 
Bogbean,  665 
Bog  plants,  480 
Bogs,  sphagnum,  84 
Bohmer's    hasmatoxylin   so- 
lution, 760 
Boletus,  61 
Bombaceae,  554,  612 
Bombax,  554,  612 
Bondicine,  576 
Boneset,  712 

false,  449 

Borage  family,  670 
Border,  386 
Bork,  293 

Borneo  camphor,  620 
Borneol,  233,  544,  676 
Borraginaceae,  670 
Boswellia,  587 

hairs  in,  282 
Botrychium,  365,  438 
Bottle,    reagent,    for    sterile 

solutions,  757 
Bougainvillea,  528 
Bouncing  bet,  530,  531 
Bower,  Virgin's,  441 
Box  tree  family,  594 
Boxwood,  439 
Brabeium,  518 
Brachycerus-a-um,  438 
Bracts,  388,  393,  402 
Bramble,  458 
Branches,  lateral,  312 
Brandy,  607 
Brasiliensis-e,  438 
Brassica,  438,  552,  553 
Brauneria,  438,  723,  724 

oil  canals  in,  224 

phytomelane  in,  260 
Brazilian  copal,  574 


INDEX. 


781 


Brazilin,  179,  180 

Bursine,  554 

Brazil-nut,  629 

Butcher's  blocks,  560 

aleurone  grains  of,  194 

Butneria,  439 

Breadfruit,  437,  516 

Butter,  cacao,  612 

Bread,  St.  John's  576 

shea,  659 

Breadstone,  39 

vegetable,  659 

Breathing  root,  306 

Butter-and-eggs,  691 

Bridelia,  593 

Buttercup,  457,  537 

Brier,  cat,  459 

Butter-fly  weed,  667  ^ 

green,  459 

Butternut,  509 

Bromeliaceae,  480 

Buttonbush,  440,  703,  704 

Bromelin,  244 

Buttons,  473 

Broom,  443 

mescal,  625 

green,  569 

Button-snakeroot,  722 

Scotch,  569 

Buttonwood,  559 

weed,  458 

Butyrospermum,  659 

Broom-rape  family,  696 

Buxaceae,  594 

Brosimum,  516 

Buxine,  594 

Brucamarine,  586 

Buxus,  439,  546.  594 

Brucea,  586 

Bruguiera,  631 

Cabbage.  553 

Brush,  472 

Cacao,    148,    211,   439,   460, 

Bryonia,  438,  709 

612 

sieve  in,  276 

butter,  612 

tendril  of,  323 

protein  in,  199 

Bryonidin,  709 

red,  612 

Bryonin,  709 

seeds,  612 

red,  709 

starch  in,  148 

white,  709 

sugar  in,  156 

Bryophytes,  76 

tree,  612 

economic  uses  of,  84 

Cactaceae,  625 

Bubbles,  air,  752 

Cactus,  439,  621,  625 

Buchania,  599 

coach-  whip,  621 

Buchu,  152,  438,  583 

family,  625 

Buckbean,  665 

Cadinene,  233,  589,  642 

Buckeye  family,  602 

Caducous,  388 

Buckthorn,  445,  457 

Cassalpinia,  439,  576 

family,  604 

coriaria,  tannin  in,  206 

Buckwheat,  445,  526,  527 

Caesalpinioideas,  567 

family,  520 

Caffeine,  162,  176,  600,  618, 

flowers,  400 

700 

protein  in,  199 

Cajuputi,  439.  452 

sugar  in,  156 

Calabar  bean,  455 

Bud,  apical,  321 

Calamint,  441 

axillary,  321 

Calamites,  100 

scale,  1  20 

Calamus,  439,  474,  479 

scaly,  321 

Calcarate,  388 

terminal,  321 

Calcium  carbonate,  200 

Buds,  321 

oxalate,  183 

Buffalo  berry,  628 

phosphate,  186 

Bugbane,  441 

Calendula,  387,  439,  718 

Bugle  weed,  434,  451 

hairs  in,  288 

Bulb,  327 

pollen  of,  405 

Bulbils,  327 

Calisaya,  439 

Bulblets,  327 

Calla,  439,  479 

Bunt,  461 

Calla-lily,  478 

Bur,  510 

Callitris,  119 

Burdock,  436,  449,  715,  717 

Calluna,  439 

Burning  bush,  600 

Callus,  277 

Bur-reed,  464 

Calophyllum,  439,  618,  619 

family,  463 

inophyllum,  212 

Bursa,  438 

Caltha,  439 

pastoris,  439 

Caltrop  family,  581 

Bursera,  587 

Calumba,  439,  539 

Burseraceae,  586 

American,  445 

Calyptrogen,  254 
Calyx,  402 

duration  of,  388 
Cambium,  314 

intrafascicular,  341 

ring,  341 
Cambogia,  439 
Camelina,  439 
Campanulaceae,  708,  710 
Campanulatae,  708 
Campanulate,  388 
Campechianus-a-um,  439 
Campestris-e,  439 
Camphene,  676 
Camphor,  439,  544,  546,  620 

Borneo,  620 

culture,  746 

Japanese,  234 

Laurus,  234 

tree,  545 
Campion,  451 
Camptosorus,  439 
Campylotropous,  379 
Canada  fleabane,  713 

moonseed,  539 
Canadensis-e,  439 
Canaigre,  527 
Canango,  542 
Canarium,  586 
Cancer  root,  695,  696 
Cane,  439,  445 
Cane-sugar,  155,  156 
Canella,  622 

bark,  622 

substitute,  622 
Canellaceae,  622 
Canna,  496 
Cannabinus-a-um,  439 
Cannabis,  439,  513 

American,  741,  742,  744 

fiber,  269 

hairs  of,  284 
Cannaceae,  496 
Cantaloupe,  710 

sugar  in,  156 
Cantharellus,  58 
Caoutchouc,  439,   513,   516, 
592 

threads,  240 
Cape  jasmine,  704 
Caper,  579 

spurge,  591 

wild,  591 

Capillaceus-a-um,  439 
Capillus-Veneris,  439 
Capitulum,  711 
Caprifoliaceae,  704 
Capsella,  438,  439,  554 

ferment  in,  244 
Capsicum,  439,  687 

protein  in,  200 
Capsule,  411 
Caraipa,  618 
Caramel,  synthetic,  159 
Carapa  oil,  589 


INDEX. 


Caraway,  440,  639 

protein  in,  200 
Carbamases,  244 
Carbohydrates,  origin  of,  157 

photosynthetic,  157 
Carbon  dioxide  assimilation, 

299,  350 

Carboniferous  age,  99 
Carbon-like  substance,  258 
Cardamom,    410,    435,    439, 
444,  494 

protein  in,  200 

starch  in,  148 
Cardinal  flower,  710 
Cardol,  596 
Carduus,  451 
Carex,  439,  47 1,  472 
Careya,  629 
Carica,  440,  542,  624 

ferment  in,  244 
Caricaceas,  624 
Carices,  472 
Carnation,  443,  531 
Carnauba-palm,  214,  474 
Carnauba-wax,  474 
Carnivorous  plants,  361 
Caroba,  691 
Carobine,  691 
Carobone,  691 
Carolianus-a-um,  440 
Carolina  pink,  661 
Carolinensis,  440 
Carota,  440 
Carotin,  493,  636 
Carpaine,  624 
Carpel,  120,  374~3?6 
Carpinus,  440,  510 
Carpophore,  417 
Carposid,  624 
Carragheen,  31 
Carrot,  440,  443 

family,  636 

protein  in,  199 

starch  in,  148 

sugar  in,  156 
Carthamic  acid,  720 
Carthamin,  720 
Carthamus,  387,  719 

pollen  of,  405 
Carum,  440,  639,  643 
Caruncle,  427 
Carvacrol,  234,  679 
Carvi,  440 
Carvone,  234 
Carya,  333 

cross-section  of  wood,  346 
Caryophyllaceae,  531 
Caryophyllene,  571 
Caryophyllus,  440,  632 
Caryopsis,  417,  466 
Caryota,  476 
Cascara,  440,  604 
Cascarilla,  440,  592 
Cascarillin,  592 
Casearia,  623 


Cashew,  435. 

nut,  458,  596 
Cassia,  360,  440,  567,  575 

purging,  567 

species  of,  567 
Cassine,  600 
Castanea,  440 

cross-section  of  wood,  346 

species  of,  512 
Castilloa,  241,  516 
Castinin,  195 
Castor  bean,  457 

aleurone  grains  in,  194 

plant,  443,  591 
Catabolism,  252 
Catalases,  245 
Catalpa,  440,  691 
Catalpin,  691 
Cataria,  440 
Catawba  grape,  606 
Cat  brier,  485 
Catechin,  180 
Catechu,  440 

black,  569 
Catha,  600 
Cathartocarpus,  440 
Cathine,  600 
Catkin,  394 
Cat  mint,  680 
Catnip,  440,  453,  680,  681 
Cat-tail  family,  463 
Cauliflower,  protein  in,  199 

sugar  in,  156 
Caulophylline,  538 
Caulophyllum,  440,  537 
Cavanillesia,  612 
Cay-Cay  butter,  586 
Ceanothus,  440,  604 
Cecidien,  334 
Cedar,  460 

apples,  115 

bastard,  581 

prickly,  454 

red,  115,  118 

uses  of,  115-117 

white,  118 

wood  oil,  589 
Cedrela,  589 
Cedron,  440,  459 

seed,  440 
Cedronin,  586 
Cedrus,  118 

Celandine,  441,  548.  551 
Celastraceae,  600 
Celastrine,  600 
Celastrus,  440,  600 
Celery,  protein  in,  199 
Celloidin,  749 
Cells,  2 

antipodal,  124 

apical,  254 

conducting,  272 

contents,  examination  of, 
246 


Cells,  contents  reaction  with 
microchemical  reagents, 
759 

cork,  290, 

division,  3 

epidermal,  277 

forms  of,  262 

guard,  279 

helping,  124 

inclusion,  207 

kinds  of,  297 

laticiferous,  239 

protecting,  277 

sclerenchyma,  266 

sclerotic,  267 

secretory,  226 

stereomatic,  268 

stone,  267 

tapetal,  121,  404 
Cellulases,  244 
Cellulose,  256 

walls,  protective,  257 
Cell- wall,  reaction  with  mi- 
crochemical reagents, 
759 

stratification  in,  258 
striation  in,  259 
Celosia,  528 
Centaurea,  440 
Centifolius-a-um,  440 
Centrifugal, development  262 
Centripetal,       development. 

262 

Centrospermae,  527 
Centrospheres,  135 
Century  plant,  489 
Cephaelis,  440,  699 
Cephalanthin,  704 
Cephalanthus,  440,  703,  704 
Cephalaria,  708 
Ceramium,  40 
Cerasin,  223 
Ceratonia,  440,  576 
Cerealis-e,  440 
Cereus,  625,  627 

night-blooming,  625 
Cetraria,  73,  440 
Cevadilla,  458 
Chakazzi  copal,  574 
Chamaelirium,  440,  491 
Chamomile,  German,  715 

Roman,  713 

wild,  452 
Chamomilla,  440 
Champagne,  607 
Chanterelle,  58 
Characeae,  26 
Charcoal,  508,  509 
Charlock,  553 
Chartreuse,  679 
Chavicol,  632 
Chebulinic  acid,  633 
Chekan,  Eugenia,  441,  63* 
Chelerythrine,  550 
Chelidonine,  550 


INDEX. 


783 


Cheliodonium,  441,  548,  550, 

551 

Chelidoxanthin,  550 
Chelone,  441,  691 
Chemical  stimuli,  248 
Chenopodiaceae,  527 
Chenopodiales,  527     , 
Chenopodium,  441,  527 

hairs  in,  282 
Cherry,  456 

bark  of,  294 

choke,  561 

cross-section  of  wood,  346 

protein  in,  199 

sugar  in,  156 

wild,  561 

black,  560 
Chestnut,  511 

American,  512 

bark  disease,  54 

cross-section  of  wood, 
346 

horse,  206,  602 

oak,  tannin  in,  206 

protein  in,  199 

Spanish,  512 

starch  in,  148 

sugar  in,  156 

tree,  440 

wild,  518 
Chests,  tea,  625 
Chewing  gum,  659 
Chew-stick,  447 
Chickweed,  435 
Chicory,  441,  716,  725 

culture,  747 

Chimaphila,  441,  455,  644 
Chinese  galls,  597 

potatoes,  492 

rice  paper,  636 

tallow  tree,  594 
Chinquapin,  512 

starch  in,  148 
Chionanthin,  661 
Chionanthus,  441,  661 
Chirata,  441,  664 
Chirayita,  441,  664 
Chiretta,  460,  664 
Chives,  485 
Chloral,  crystals,  762 
Chloranthy,  391 
Chlorenchyma,  366 
Chlorococcum,  72 
Chlorophora,  516 
Chlorophycese,  T7,  20 
Chlorophyll,  138,  158 
Chloroplastids,  137 
Chloroplasts,  137 
Chlorosis,  391 
Chlor-zinc-iodide   solution, 

760 

Choke  cherry,  561 
Chondrodendron,  441,  539 
Chondrus,  31,  441 
Choripetalae,  504 


Choripetalous,  383 
Chorisepalous,  383 
Chorisia,  612 
Chorisis,  390 
Christmas  holly,  600 
Chromatin,  136 
Chromatophore,  136 

fixed  oils  in,  210 
Chromene,  180 
Chromic  a*cid,  756 
Chromogen,  179 
Chromophores,  179 
Chromoplastids,  137,  138 

occurrence  of,  181 
Chromosomes,  136 
Chrozophora,  593 
Chrysanthemum,    441,    714, 

718,  724,  726 
Chrysarobinum,  441 
Chrysophyllum,  441,  659 
Chrysosplenium,  441,  556 
Chymases,  244 
Cicely,  sweet,  643 
Cichoriaceae,  711 
Cichorium,  441,  716,  725 
Cicuta,  441,  575,  642 
Cigar  boxes,  117,  589 
Cimicifuga,  441,  532,  533 
Cinchona,  441,  697 

cultivated,  546,  690,  698 

plantation,  698 

species  of,  699 

substitute,  606,  620 
Cineol  containing  oil,  544 
Cinereus-a-um,  441 
Cinnamic  acid,  572 

aldehyde,  544 
Cinnamodendron,  622 
Cinnamomum,  441,  543,  544, 

545 
Cinnamon  cultivation,  545 

cutting,  545 

oil,  544 

starch  in,  148 
Cinquefoil,  456 
Circaea,  441,  634 
Circinate,  364 
Circumcissile,  413 
Circumnutation,  360 
Cirrhiferous,  357 
Cissampelos,  441 
Cistus,  hairs  in,  282 
Citral,  233,  234.  564.  583 
Citron,  441,  584 
Citronellol,  564,  579 
Citrullus,  441,  708,  710 
Citrus,  441,  583.  584 
Cladonia,  72,  74 
Claptonia,  531 
Claret,  607 
Clavatus-a-um,  441 
Clava-Herculis,  441 
Clavaria,  58 
Clavariaceae,  59 
Claviceps,  441 


Claviceps  purpurea,  52 

Claw,  385 

Clearing  agents,  755,  756 

Cleavers,  446 

Cleaverwort,  436 

Cleft,  356 

Clematis,  441,  537 

cork  in,  293 
Climbers,  324 

root,  324 
Clinopodium,  441 
Clitoria,  575 
Clotbur,  462 
Clove,  440,  441,  632 

protein  in,  200 

starch  in,  148 

tree,  445 
Clover,  567,  576 

prairie,  449 

sweet,  452 
Club-like,  441 
Clusia,  619,  620 
Cnicin,  723 
Cnicus,  441,  723 
Coach-whip  cactus,  621 
Coal  age,  99 

deposits,  119 
Coalescence,  390 
Coca,  442,  580 

family,  580 

seedling,  745 
Cocaine,  163,  170,  581 
Cocci,  13 
Coccos  oil,  623 
Cocculus,  442,  539 
Coccus,  442,  516,  531,  606, 
621,  627 

lacca,  238 

Cochineal  insect,  627 
Cochlearia,  442,  553 
Cochlospermum,  223,  622 
Cocillana,  516 
Cocklebur,  462 
Cock's-comb,  528 
Cocoa  (see  Cacao) 

Brazilian,  603 
Cocoa-nut,  212,  474 

palm,  474 
double,  427 
fruit,  413 

protein  in,  199 
Cocos,  474.  476 

fruit,  413 

Codeine  crystals,  767 
Coffea,  442,  700 
Coffee,  442,  700 

aroma,  700 

caffeine  in,  162 

cultivation,  700 

Kentucky,  447 

picking,  702 

protein  in,  199 

roasting,  700 

substitutes,  6n,  716 

sugar  in,  156 


INDEX. 


Coffee  tree,  575,  701 

wild,  632,  707 
Coffeol,  700 
Cohesion,  390 
Cohosh,  434 

black,  532 

blue,  440,  537 
Cola,  614,  615 

caffeine  in,  162 

family,  612 
Colchicum,  442,  485 
Cold  frames,  731 
Colic-root,  435,  485 
Coliguaya,  593 
Collateral  mestome  strands, 

Collenchyma,  265 
Colletin,  606 
Collinsonia,  442 
Colloidal,  140 
Colocynth,  708 

fruit,  410,  424 

seed,  424 
Colocynthis,  442 
Color  in  autumn  leaves,  178 

in  lichens,  72 

principles,  chemistry,   179 

substances,    cell-sap,    176, 
181 

substances,  distribution  of, 

181 
Coloring  of  flowers,  artificial, 

182 
Colors,  cell-sap,  176 

function  of,  181 
Coltsfoot,  387,  445,  461,  723 
Colubrina,  606 
Columbine,  wild,  536 
Columbo,  539 
Combretaceag,  633 
Combretum,  633 

hairs  in,  282 
Comfrey,  460,  671 
Commelina,  442,  480 
Commelinaceae,  480 
Commiphora,  442,  586 
Common    mossy    stonecrop, 

556 

Communis-e,  442 
Compass  plant,  723 
Complete  flower,  298 
Compositae,  711,  712 

flowers  of,  387 

hairs  in,  288 
Compound  leaves,  356 
Comptonia,  509 
Concentric  mestome  strands, 

342 

Conduplicate,  364 
Condurango,  668 
Cones,  375 
Confluent,  381 
Conglutin,  195 
Conidia,  41 
Conifera-um,  442 


Coniferse,  uses  of,  117 
Coniferin,  169,  170,  171,  489 
Conium,  442,  638,  640 
Conjugatae,  17 
Conjunctive  tissue,  313 
Connate-perfoliate,  356 
Connective,  122,  381 
Conopholis,  695,  696 
Consolodin,  673 
Contortae,  660 
Contraction  of  roots,  319 
Contrayerva,  444 
Convallamarin,      170,     442, 

486 

Convallaria,  487 
Convolute,  364 
Convolvulaceae,  668 
Convolvulus,  442,  669 
Copaiba,  442,  571,  574 

substitute,  621 
Copal,  American,  574 

Brazilian,  574 

Chakazzi,  574 

East  Indian,  587 

Inhambane,  574 

resins,  574 

Sierra  Leone,  574 

Zanzibar,  574 
Copalchi,  592 
Copalchin,  592 
Copernicia,  474 

cerifera,  214 
Copper  acetate  solution,  761 

treatment  of  water,  8 
Coptis,  442 
Coral  root,  442 
Corallorhiza,  442 
Corchorus,  269,  609 
Cordifolius-a-um,  442 
Coriamyrtin,  595 
Coriander,  442 

protein  in,  200 
Coriandrum,  442,  637 
Coriaraceae,  594 
Coriaria,  594 
Coriarious-a-um,  442 
Cork  cells,  290 

development,  293 
Corm,  329.  477 
Corn,  467 

Black  Mexican,  178 

cockle,  434,  446 
seed,  426 

Indian,  462 
root-tip,  300 

oil  in,  213 

protein  in,  199 

silk,  178 

starch  in,  148 

sugar  in,  156 
Cornaceae,  643 
Cornel,  442 
Cornin,  643 
Cornus,  442,  388,  643 
Corolla,  382,  402 


Corona,  623 
Coronilla,  442,  575 
Cortex,  310 

secondary,  313 
Corydaline,  551 
Corydalis,  209,  551 
Corylus,  442,  510 
Corymb,  394 
Corymbine,  702 
Corynine,  702 
Cotoneaster,  562 
Cotton,  447 

fiber,  269 

protein  in,  199 

Sea  Island,  610 

seed,  oil  in,  213 

oil,  611 
Cotula,  442 
Cotyledon,  299,  426 
Couch-grass,  468 
Coumarin,  472 

in  polypodium,  96 
Couroupita,  629 
Corillea,  581 
Cowhage,  452,  576 
Cranberry,  656 

American,  655 

European,  656 

fruit,  417 

small,  655 

tree,  704 
Cranesbill,  446 
Crassulacea?,  556 
Cratsegus,  442,  565 
Crateriform,  388 
Cratoxylum,  619 
Crawley  root,  453 
Cream  nut,  630 
Crea.m-of-tartar  tree,  612 
Crecopia,  516 
Cremocarp,  417,  636 
Crenate,  356 
Crenulatus-a-um,  442 
Creosote,  512 

bush,  580 
Cress,  Indian,  579 
Cretian  origanum,  679 
Crinum,  492 
Crispus-a-um,  442 
Croceine  M.  O.  O.,  182 
Crocin,  493,  704 
Crocus,  442,  493,  704 

pollen  of,  404.  405 

stigma  of,  405 
Crops,  harvesting  of,  738 
Cross-pollination,  560 
Cross-section,  749 
Crotalaria,  442,  575 
Crotin,  198 
Croton,  443,  591-593 

oil  in,  213 
Crowfoot,  457,  532 
Crown-galls,  335 
Crucifer-a-um,  443 
Crucifers,  551,  574 


INDEX. 


785 


Cruciger-a-utn,  443 

Curare  poison,  539 

Cryptogams,  5 

Curarine,  662 

vascular,  86 

Curatella,  615 

Crystal,  769 

Curcas,  oil  in,  213 

biaxial,  774 

Curcin,  198 

clusters,  185 

Curcuma,  494 

codeine,  767 

protein  in,  200 

columnar,  183 

Curcumin,  496 

fibers.  187 

Currant,  457,  558 

hexagonal,  774 

Buffalo,  558 

h'ydrastine,  77O 

fetid,  558 

membrane,  189 

protein  in,  199 

micro,  187 

sugar  in,  156 

microtechnic,  776 

Cuscuta,  670 

monoclinic,  183,  184,  774 

Cuscutin,  670 

of  fixed  oils,  211 

Cusparia,  443,  585 

of  reagents,  762 

Cusso,  443,  447,  565 

orthorhombic,  183,  774 

Custard  apple,  543 

piperine,  771 

family,  541 

sand,  188 

Cutin,  277 

solitary,  183 

Cutose,  257 

sphere,  192 

Cyanol,  P.  P.,  182 

strychnine  crystals,  769 

Cyanophyceae,  8 

tetragonal,  183,  774 

glycogen  in,  154 

triclinic,  774 

Cyanus,  443 

uniaxial,  774 

Cycads,  in 

Crystalline  wax,  216 

Cyclamen,  656 

Crystallographic  method  of 

hairs  in,  282 

examination,  767 

Cydonia,  560 

Crystalloidal,  140 

Cylindric  leaves,  349 

Crystalloids,  193,  199 

Cyme,  395 

Cubeb,  443,  504 

dibrachious,  395 

substitute,  541 

helicoid,  395 

Cubebin,  crystals,  768 

rrionobrachious,  395 

Cuckoo-pint,  437 

Cymene,  643 

Cucumber,  710 

Cyminum,  443 

protein  in,  199 

Cynara,  726 

squirting,  444,  709 

Cynips,  511 

sugar  in,  156 

Cynoglossine,  6?3 

tree,  540 

Cynoglossum,  443,  673 

sour,  612 

Cynomorium,  519 

Cucumis,  443,  710 

Cyperaceae,  472 

Cucurbita,  443,  709 

Cyperus,  443,  472,  473 

Cucurbitaceae,  708 

Cypripedium,  443,  496,  498, 

Cudbear,  74 

501 

Cudrania,  516 

Cystoliths,  200 

Cud  weed,  446 

Cystopus,  44 

Cultivated  and  wild  plants, 

Cystotyles,  201 

value  of,  739 

Cytases,  244 

Cultivation      of      medicinal 

Cytisine,  575 

plants,  727 

Cytisus,  443,  569 

progress  in,  744 

Cytology,  13^*^**      -^ 

Culver's  root,  450,  689 

Cytoplasm,  2,  135 

Cumarin,  173 

Cumin,  443,  643 

Daisy,  712 

oil,  643 

fleabane,  713 

Cuminum,  443,  643 

white,  718,  724 

Cunila,  443,  681 

Damascenus-a-um,  443 

Cup  or  bur,  510 

Damiana,  623 

Cupana,  443 

Damianin,  623 

Cuphea,  628 

Dammar,  black,  587 

Cupule,  420 

Dandelion,  460,  712 

Curanga,  691 

hairs  in,  288 

Curanjiin,  691 

Daphne,  443,  627 

Curare,  662 

Daphnin,  170 

D-arabinose,  169 

Dark  field  illumination,  765 

Date  palm,  208,  473 
endosperm  in,  265 

Dates,  475 

Datisca,  625 

Datiscaceae,  624 

Datiscin,  169,  625 

Datura,  443,  682,  684 
ferment  in,  244 

Daucus,  443 

Day-flower,  442,  480 

Deadly  nightshade,  684 

Decandrus-a-um,  443 

Deciduous,  388 

Definite  inflorescence,  394 

Dehiscence,  411 

Dehydrating  agent,  755,  756 

Delafield's  haematoxylin  so- 
lution, 760 

Delphinium,  443,  535,  574 

Dentate,  356 

Dentatus-a-um,  443 

Dermatogen,  253 

Derris,  575 

Descent  of  plants,  133 

Desmids,  17 

Desmodium,  361,  443 

Development,  arrested,  391 
of  stomata,  368 

Devil's  apron,  30 

Devonian  age,  99 

Dewberry,  Northern,  563 

Dextrin,  147 

Dextro-glucose,  155 

Dextrose,  155,  563 

Diandrous,  381 

Dianthus,  443 
species  of,  531 

Diaporthe  parasitica,  54 

Diastase,  242 

Diatomaceous  Earth,  38 

Diatoms,  35 

Dibrachious  (cyme),  395 

Dicentra,  443,  551 

Dicotyledonous  stem  struc- 
ture, 339 

Dicotyledons,  120,  501 

Dictamus,  225,  443 

Dicypellium,  544,  546 

Didymus-a-um,  443 

Didynamous,  381 

Diervilla,  443,  ?o? 

Digitalin,  169,  170 

Digitalis,  443,  690 
hairs  of,  284,  285 
section  of  leaf,  372 
seedlings,  743 

Digitalose,  169 

Digitonin,  169 

Digitoxin,  169 

Dill,  436 
garden,  643 
oil,  643 
protein  in,  200 


786 


INDEX. 


Dillenia,  615 
Dilleniaceae,  615 
Dimorphic  flowers,  399 
Dioicus-a-um,  444 
Dionaea,  362,  554 
Dioscorea,  444,  492 

stem  of,  322 
Dioscoreaceae,  492 
Diosphenol,  582 
Diospyros,  444,  659 

hairs  in,  282 
Dipentene,  722 
Diphyllus-a-um,  444 
Diplococci,  14 
Dipsacaceae,  707 
Dipsacus,  444,  708 
Dipterocarpaceas,  620 
Dipterocarpus,  620 
Dirca,  444,  627 
Disaccharose,  154 
Discaria,  606 
Discoid  head,  711 
Disk-flower,  711 
Dissepiment,  411,  378 

false,  378 
Dissotis,  634 
Distichous,  363 
Dita,  435 

Ditch  stonecrop,  454,  556 
Dittany,  443 

American,  682 
Divergence,  363 
Divided,  356 
Divi-divi,  tannin  in,  206 
Divining  rod,  558 
Division,  internal,  5 
Doassansia,  67 
Dock,  curled,  523 

sorrel,  458 
Dodder,  670 
Dogbane,  436 

family,  664 

spreading,  664 
Dog's-tooth  violet,  485 
Dogwood,  442 

family,  643 

flowering,  643 

Jamaica,  448,  575  . 
.Domesticus-a-um,  444 
Domingensis-e,  444 
Doona,  621 
Dorema,  444,  639 
Dorsal  pneumatic  tissue,  366 

suture,  377 
Dorsiventral  flowers,  393 

leaves,  349,  366 
Dorstenia,  444 
Double  flowers,  714 

staining,  762 
Douglas  fir,  114 

spruce,  119 
Dracaeno,  489 
Dracontomelum,  599 
Dragon's  blood,  474,  488 
Dragon  tree,  489 


Drimys,  540 
Drosera,  361,  444,  554 
Droseraceae,  554 
Drugs,  curing  of,  738 

drying  of,  737,  738 

physiological    testing    of, 
248 

selection  of,  737 
Drupe,  418,  426 
Driizenzotten,  222 
Dryobalanops,  620 
Dryopteris,  87,  90,  92,  444 

hairs  of,  284 

Dry  yeast,  lecithin  in,  214 
Duckweed,  450 

family,  478 

Ducts  (see  Tracheae),  273 
Dulcamara,  444,  684 
Dulce,  Irish,  34 
Dulcis-e,  444 
Dulcitol,  156 
Duration      of      calyx      and 

corolla,  388 
Dutch  clover,  472 
Dutchman's  breeches,  550 
Dwarf  branch,  374 
Dye,  leather,  633 
Dyer's  broom,  574 
Dyes,    aniline,    as    staining 
agents,  75? 

non-aniline,     as     staining 

agents,  757 

Dynamic  centers  of  cell,  140 
Dysentericus-a-um,  444 
Dzaini,  562 

Early  sweet  blueberry,  653 
Eau  D'Ange,  632 

de  Creole,  620 
Ebenaceae,  444,  659 
Ebenales,  658 
Ebony,  444,  659 

black,  659 

family,  659 

green,  659 

red,  659 

striped,  659 

white,  659 
Ecballium,  444,  709 
Echinacea,  723 

oil  canals  in,  224 

phytomelane  in,  260 
Echinate,  354 
Echinocarpus,  607 
Ecology,  i 
Edestin,  195 
Eelgrass,  466 
Egg  apparatus,  298 

cell,  124,  298 

plant,  688 
Elseagnaceae,  628 
Elaeagnus,  628 
Elaeis,  474 
Elaeocarpaceae,  607 
Elaeocarpus,  608 


Elastic,  444 
Elastica,  241,  592 
Elasticity,  774 
Elasticus-a-um,  444 
Elaterin,  709 
Elaterium,  444,  709 
Elaters,  82 
Elder,  458 

American,  706 

black,  706 

mountain,  706 

red-berried,  706 
Elecampane,  448,  720 
Elemi,  Bengal,  586 

Manila,  586 

resin,  586 

West  India,  586 
Eleocharis,  444,  472 
Elettaria,  444,  494 
Eleusine,  467 
Elm,  461,  512 

American,  512 

cross-section  of  wood,  346 

family,  512 

slippery,  513 

white,  512 
Eluteria,  444 
Emarginate,  355 
Emasculated,  451 
Embryo-sac,  108,  120,  298 
Emodin,  170 
Emulsins,  243 

Enchanter's  nightshade,  634 
Endocarp,  410 
Endodermis,  310 
Endosmosis,  251 
Endosperm,  108,  127,  425 

of  date  palm,  265 

structure  of,  429 
Endospore,  12,  41 
Endothecium,  404 
Endothia  radicalis,  54 
Entada,  575 
Enterolobium,  575 
Entomophilous,  402 
Environment,  130 
Enzymes,  241 

diastatic,  242 
Eperua,  576 
Ephemeral,  388 
Epicarp,  410 
Epicotyl,  299,  426 
Epidermal  cells,  277 
Epidermis,  309,  369 
Epigaea,  444,  644,  649 
Epigeous  shoot,  321,  322 
Epigynous,  389 
Epilobium,  634 
Epipactis,  503 
Epiphytes,  306 
Equisetaceae,  444 
Equisetales,  96 
Equisetums,  96,  444 
Equitant  leaves,  349 
Erectus-a-um,  444 


INDEX. 


787 


Ergot,  52,  155,  441,  444 
Ericaceae,  444,  644 

microsublimates  of, 

173 

Ericales,  644 
Ericolin,  655 
Erigeron,  444,  713 
Eriobotyra,  562 
Eriodendron,  611 
Eriodictyon,  444,  670 

hairs  of,  284,  286 
Erysimum,  445,  553 
Erytaurin,  664 
Erythraea,  664 
Erythronium,  485 
Erythrophlceum,  575 
Erythroxylaceae,  580 
Erythroxylon,  445,  580 
Eschscholtzia,  547,  550 
Esculentus-a-um,  445 
Esparto,  472 
Esters,  234 
Estivation,  389 
Etaerio,  419 
Ether,  phenol,  234 
Euasci,  47 
Eucalyptol,  631 
Eucalyptus,  445,  631 

kino,  631 

oil,  631 

seedling,  745 

species  of,  631 
Eucitrus,  583 
Eugenia,  445,  631 
Eugenol,  234,  544,  546 
Euonymus,  239,  445,  600 
Eupatorin,  713 
Eupatorium,  445,  712 
Euphorbia,    445,    591,    592, 

594 

Euphorbiaceae,  590 
Euphorbium,  593 
Euphorbon,  593 
Europaeus-a-um,  445 
Euryale,  532 
Evening  primrose,  436,  634, 

635 

family,  634 
Evergreen,  459 
Evernia,  73 
Evolution,  129,  247 
Excelsin,  195 
Excelsus-a-um,  445 
Excoecaria,  592 
Exine,  123,  404 
Exocarp,  410 
Exodermis,  309 
Exogonium,  445,  668 
Exosmosis,  251 
Exospores,  41 
Exothecium,  404 
Experimental     farms,     732- 

735 

Extraordinary  ray,  774 
Extrorse,  380 


Fabiana,  684 
Fagaceae,  511 
Fagales,  510 

Fagopyrum,  445,  526,  527 
Fagus,  445 

species  of,  512 
Fairy-ring  fungus,  58 
False  beech-drops,  644 

dissepiment,  378 

flax,  439 

hellebore,  462,  537 

indigo,  435,  438 

mitre  wort,  460,  556 

nettle,  438 

Solomon's  seal,  484,  485 

spikenard,  484 

unicorn  root,  491 

winter's  bark,  622 
Fan  palms,  473 
Farfara,  445 
Farinosae,  480 
Farinosus-a-um,  445 
Farms,    experimental,    732- 

735 

Fastigiatus-a-um,  445 
Fats,  210 

physiology,  216 
Fatty  oils,  546 

resins,  238 
Fegatella,  272 
Fennel,  445,  639 

flower,  453 

protein  in,  200 
Ferments,  241 

in  stinging  hairs,  287 

in  yeast,  49 

microchemistry  of,  245 
Fern,  flowering,  454 

fossil,  104 

male,  445 

palms,  in 

sensitive,  453 

used  in  medicine,  96 

walking,  92 

water,  94 
Fertile,  121 
Fertilis-e,  445 
Fertilization,  125,  397 
Ferula,  445,  639 
Fetid,  445 
Fever  bush,  438 

hay,  726 
Fibers,  bast,  268 

isolation  of,  270 

sclerenchymatous,  268,270 

strength  of,  269 
Fibrovascular  strand,  313 
Ficus,  241,  445,  513,514,515 

ferment  in,  244 

latex  in,  240 

species  of,  516 
Field  sorrel,  524,  525 

penny  cress,  553 
Fig.  515 

ferment  in,  244 


Fig,  Indian,  626,  627 

protein  in,  199 
Figwort  family,  688 
Fiji  oil,  519 
Filament,  379,  404 
Filbert,  442,  510 
Filicales,  87 
Filix-mas,  445 
Fir,  213,  434 

California  silver,  na 

red,  119 

Scotch,  117 

tannin  in,  206 

white,  119 
Fisetin,  180 
Fishberries,  539 
Fish  poison,    517,   539,   604, 

606 

Fistula,  445 
Fixing  agents,  755 
Flacourtiaceae,  622 
Flats,  plant,  730 
Flavon,  170 
Flavone,  180 
Flax,  450 

family,  579 
Flaxseed,  oil  in,  213 

protein  in,  199 

structure  of,  428 
Fleabane,  444 

Canada,  713 

daisy,  713 

Philadelphia,  713 

sweet  scabious,  713 
Flea  seed,  456  ,     - 

Fleur-de-lis,  448 
Floral  envelopes,  382 

leaves,  120,  375 
Florets,  711 
Florida  moss,  480 
Flour,  gluten,  196 

Graham,  196 
Flower,  374 
Flowers,  classes  of,  392 

cleistogamous,  391 

complete,  392 

diagrams,  505 

double,  390,  714 

inner  structure  of,  402 

insect,  718 

ligulate,  395,  7H 

of  Angiosperms,  375 

of  Compositae,  387 

of  Gymnosperms,  375 

of  Solanaceae,  385 

outer  morphology  of,  374 

parts  of,  374 

stalks,  376,  402 

sun,  447 

tubular,  39  ',  711 

types  of,  3"3 
Flueggea,  593 
Fceniculum,  445,  639 

aleurone  grains  of,  194 
Foetida,  629 


788 


INDEX. 


Foetidus-a-um,  445 

Fog-fruit,  450 

Folia  Malabanthri,  568 

Follicle,  419 

Fontinalis,  85 

Food,  bird,  696 

of  plants,  248 
Fore-leaves.  393.  466 
Forget-me-not,  453,  670 
Formaldehyde,  234 
Forms  of  leaves,  354 

of   plants,    alterations   in, 

332 

Fossil  Coniferae,  119 
Fouquieria,  621 
Four  o'clock  family,  528 
Foxglove,  443,  690 
Fragaria,  445,  566 

fruit,  415 

species  of,  567 
Fragilaria,  37 
Fragrance    due    to    volatile 

oils,  234 
Fragrans,  445 
Fragrant,  445 
Frames,  cold,  731 
Frangula,  445 
Frangulin,  169,  170   w 
Frankincense,  587 
Frasera,  445 
Fraseri,  446 
Fraxetin,  66 1 
Fraxin,  169,  170,  661 
Fraxinus,  446,  66 1 

glandular  hairs  in,  230 
Fremontia,  615 
French  plum,  562 
Fringe  tree,  441,  661 
Fructose,  154,  155 
Fructosidase,  242 
Fruit  acids,  563 

ethers,  564 

jellies,  243 

outer  morphology  of,  408 

structure  of,  421 

sugars,  155,  563 
Fruits,  classification  of,  421 

different  types  of,  409 
Fuchsia,  634 
Fuchsin,  as  staining  agent, 

7S7 

Fucose,  154 
Fuller's  teasel,  708 
Fulvus-a-um,  446 
Fumaria,  209,  446,  547,  550 
Fumariaceae,  209 
Fumarine,  548,  550 
Fumitory,  446,  550 

European,  550 
Funaria,  85 
Function  of  leaf,  350 
Fungi,  7.  40 

constituents  of  41 

coral,  58,  59 

detection  of,  70 


Fungi,  economic  uses,  65 

edible,  59 

ferments  of,  242,  244 

gill, 

glycogen  in,  154 

groups  of,  41 

imperfecti,  70 

jelly,  59 

leather,  59 

poisonous,  6l 

pore,  59 

rust,  65,  68 

smut,  65 

stinck-horn,  59 
Fungus  chirurgorum,  65 
Funifera,  627 
Fusanus,  519 
Fustin,  169,  170 

Galactose,  169 
Galangal,  494 
Galbalus,  419 
Galbanum,  639 
Galeopsis,  446 
Galetae,  388 
Galium,  446,  697,  704 
Gallicus-a-um,  446 
Galls,  206,  334,  446,  511 

Chinese,  597 

crown,  335 

fungus,  334 

hard.  334 

Japanese,  597 

of  Terminalia,  633 

soft,  334 

Gamboge,  597,  618,  619 
Gamete,  5,  298 
Gametophyte,  75,  108,  298 
Gamopetalous,  385 
Gamosepalous,  385 
Garcinia,     446,     618,     619, 

620 
Garden  bean,  576 

beets,  protein  in,  199 

heliotrope,  670 

lilac,  661 

pea,  576 

rue,  585 

strawberry,  566 
Gardenia,  446,  704 
Garlic,  435,  485 

mustard,  553 

protein  in,  199 
Gaultherase,  243,  644 
Gaultheria,  446,  644,  650 
Gaultherin,  169,  170 
Gaylussacia,  446,  652 

fruit,  414 
Gelidium,  34 
Gelsemium,  446,  661 
Genista,  446,  574,  575 
Gentian,  446,  663 

American,  664 

bottle,  663 

closed,  663 


Gentian  family,  663 
fringed,  664 
horse,  706 
rhizome  of,  331 
violet,   as   staining  agent, 

757 

yellow,  663 
Gentianaceae,  663 
Gentianales,  660 
Gentinin,  169 
Gentisein,  180 
Geotropism,  negative,  320 

positive,  302 
Geraniaceae,  578 
Geraniales,  577 
Geraniol,  233,  564,  579,  583 
Geranium,  446,  571 
family,  578 
fruit,  409 
grass  oil,  472 
hairs  in,  282 
rose,  579 

Geranyl  acetate,  234 
Gerardia,  purple,  693 
German  chamomile,  715 
Germander,  460 
Germination,  time  of,  730 
Geum,  446 
Gigartina,  33,  446 
Gilead  balsam,  587 
Ginger,  462,  494 
beer,  49 
family,  494 
grass  oil,  472 
protein  in,  200 
starch  in,  148 
wild,  437,  520 
Ginseng,  305,  454.  636,  638 
cultivation  of,  735 
family,  636 
Girardinia,  517 
Githago,  446 
Glaber-bra-brum,  446 
Glabrous,  369 
Glaeocapsa,  72 
Glandular,  354 
Glandulifer-a-um,  446 
Glandulosus-a-um,  446 
Glans,  420 
Glaucium,  446,  550 
Glaucous,  370 
Glechoma,  681 
Gleditschia,  575 
Gliadins,  195 
Globe  artichoke,  726 
Globoids,  193 
Globulins,  192 
Globulus,  446 
Glosocapsa,  8 
Gloiopeltis,  34 
Gluco-alkaloids,  172 
Glucose,  154 
Glucosidal  resins,  238 
Glucosidase,  242 
Glucoside,  155,  167 


INDEX. 


789 


Glucoside,  classification    of, 
169 

dextrose,  169 

distribution  of,  169 

function  of,  172 

microchemistry  of,  171 

rhamnose,  169 
Glumes,  466 
Glumiflorae,  466 
Glutamin,  253 
Glutelins,  194,  195 
Gluten,  196 

flour,  196 

Glutinosus-a-um,  446 
Glutinous,  446 
Glycerin-jelly,  763 
Glycine,  576 
Glycinin,  195 
Glycocoll,  192 
Glycogen,  154 
Glycoside,  167 
Glycyphyllin,  169 
Glycyrrhiza,  446,  568 
Gnaphalium,  446 
Gnidia,  627 
Goa  powder,  441 
Goat's  beard,  461 
Goldenrod,  459,  712,  726 

anise-scented,  722 

nigh,  721 

Golden  seal,  448,  532          ; 
Gold  flower,  441 
Goldthread,  442 
Gonidium,  71 
Goodyera,  503 
Gooseberry,  457,  557 

fruit,  418 

protein  in,  199 

sugar  in,  156 
Goosefoot,  441,  527 
Gossypitrin,  169 
Gossypium,  447,  6iO 

fiber,  269 
Gouania,  447,  606 
Gourd,  443 

family,  708 
Gracilaria,  34 
Graham  flour,  196 
Grain,  417 

pollen,  298 
Graminales,  466 
Gramineae,  447,  466 
Granatum,  447,  629 
Grape,  462,  606 

fern,  Virginia,  365 

fruit,  584 

protein  in,  199 

seed,  oil  in,  213 

sugar,  155,  606 

sugar  in,  156 

vine,  606 
Grass,  447 

beard,  436 

family,  466 

holy,  448 


Grass  of  Parnassus,  556 

panic,  454 

pepper,  450,  553 

scurvy,  442,  553 

sweet  vernal,  436 

worm,  459 
Gratiola,  447,  691 
Gratiolin,  691 
Graveolens,  446 
Gravity,  influence  of,  301' 
Greek  valerian,  671 
Grenadier's     borax-carmine 
solution,  760 

haematoxylin    solution, 

760 

Grevillea,  518 
Grewia,  609 
Grias,  629 
Grifnthsia,  40 
Grimmia,  85 
Grindelia,  447,  713 
Gromwell,  450 
Groundsel,  459 

tree,  437 

Growing  point,  253 
Growth,  factors  influencing, 

246,  247 
Guaiac,  447 

Guaiacum,  447,  580,  581 
Guarana,  162,  447,  454,  603 
Guarea,  516 
Guava,  632 
Guayava,  632 
Guazuma,  615 
Guelder-rose,  wild,  704 
Gulf  weed,  31 
Gum,  218,  565,  599 

acajou,  599 

anacardium,  223 

arabic,  222,  569 

balata,  659 

chagual,  223 

chewing,  659 

chicle,  659 

cocoa-palm,  223 

East  Indian,  223 

exuding,  447 

moringa,  223 

plant,  447 

red,  574 

resin,  225,  236 

spruce,  119 

tragacanth,  218,  569,  570 

tree,  sweet,  558 

yellow.  574 
Gumbo,  611 
Gummifer-a-um,  447 
Gummy,  444 
Gurjun  balsam,  621 
Gurjunic  acid,  621 
Gutta-percha,  241,  658 
Guttiferae,  618 
Guvacine,  474 
Gymnocladus,  447,  575 
Gymnosperms,  101 


Gymnosperms,    flowers     of, 

375 

groups  of,  in 
Gymnosporangium,  115 
Gynaecium,  376 
Gynandrous,  382 
Gynocardia,  623 
Gypsophila,  447,  531 
Gysbertsiana,  621 

Habenaiia,  447,  499,  500 
Hadrome,  312 
Haematoxylin,  180 
Haematoxylon,  447,  571 
Hagenia,  447,  565,  566 
Hairs,  abietiform,  287 

candelabra,  287 

crystal  containing,  287 

false  plant,  290 

glandular,  222,  228,  281 

hooked,  286 

lignified,  290 

nonglandular,  283 

papillose,  286 

peltate,  286 

plant,  279 

shaggy,  285 

stellate,  286 

stinging,  287 

types  of,  281 

uniseriate,  286 
Hamamelidaceae,  558 
Hamamelis,  447,  558,  559 
Hanburii,  447 
Hand  microtome,  749 
Hardening  agent,  755,  756 
Hard  galls,  334 
Hardhock,  459 
Hard  rush,  493 
Hardwickia,  571 
Harvesting  of  crops,  738 
Hashish,  516 
Haustoria,  306,  518 
Haw,  black,  704 
Hawthorn,  442,  565 
Hay  fever,  726 
Hazelnut,  442,  510 

Chilian,  518 

oil  in,  213 

protein  in,  199 
Hazelwort,  437 
Head,  395 
Heart's  ease,  462 
Heath,  444 

family,  644 
Heather,  439 
Hedeoma,  447,  676 
Hedera,  447,  636 
Hederic  acid,  636 
Hedge  hyssop,  447.  452; 
Helenium,  447,  723 
Helianthemum,  447 
Helianthenin,  150,  726 
Helianthus,  447,  725 
Helicteres,  615 


790 


INDEX. 


Heliotrope,  447 

garden,  670 
Heliotropism,  349 
Heliotropium,  447,  670 
Helixin,  636 
Hellebore,  447 

black,  537 

false,  537 
Helleborein,  537 
Helleborus,  447,  537 
Helonias,  491 
Hemiasci,  47 
Hemlock,  113,  461 

poison,  442,  638,  640 

tannin  in,  205,  206 

(Tsuga),  119 

water,  441,  575,  642 
Hemp,  439 

fiber,  269,  514 

nettle,  446 

oil  in,  213 

sisal,  492 

yellow,  625 

Hempwood,  climbing,  452 
Henbane,  448,  684 
Henequen,  492 
Henna  plant,  629 
Hepaticae,  80,  447 
Herb,  annual,  329,  330 

biennial,  330 

perennial,  330 

quinine,  664 

Herba     Centaurii     Minoris, 
664 

cochleariae,  553 
Herbaceous,  447 
Herbaceus-a-um,  447 
Herbs,  329 
Hercules,  club  of,  441 
Hermaphrodite,  392 
Herniaria,  531 
Hesperidin,    151.    169,    i?o, 

585 

Hesperidium,  419 
Hesperis,  447,  583 

hairs  in,  282 
Heterocysts,  n 
Heterosporous,  87 
Heuchera,  447,  556 
Hevea.  241,  447,  592,  594 
Hexose,  154 
Hibiscus,  448,  611 
Hickory,  333,  509 

cross-section  of  wood,  346 
Hicoria,  365,  509,  510 
Hierochloe,  448,  472 
High-bush  huckleberry,  652 
Hilum,  425 

of  starch  grain,  144 
Hinna,  629 
Hippocastanaceae,  602 
Hippocastanum,  448 
Hirsute,  354 
Hirsutus-a-um,  448 
Hispid,  354 


Hispidus-a-um,  448 
Histology,  i 
Hoarhound,  white,  676 
Hold-fast,  30 
Holly,  448 

American,  600 

Christmas,  600 

dahoon,  600 

European,  600 

family,  600 

leaved  barberry,  436 
Hollyhock,  435,  609,  611 
Homalium,  623 
Honesty,  553,  554 
Honey,  402 

dew,  157 

poison,  402  , 

Honeysuckle,  450 

bush,  443,  707 

family,  704 
Hopea,  621 
Hop,  hornbeam,  454 

substitute,  606,  621 

tree,  585 
Hops.  448,  SIS 
Hordeum,  448,  467,  468 
Horehound,  fetid,  437 

water,  451 
Hornbeam,  440,  510 
Horsebalm,  442 

chestnut,  434,  448,  602 

gentian,  706 

mint,  679 

radish,  553 

tails,  96,  444 
Hound's  tongue,  443,  673 
Houstonia,  448,  697 
Hoyer's  picro-carmine  solu- 
tion, 760 
Huckleberry,  446,  654 

black,  652 

fruit,  414 

sugar  in,  156 
Humulene,  508,  509 
Humulus,  448,  514 

hairs  in,  282 
Humus,  249 
Hura,  592 
Hyacinth,  485 
Hydnocarpus,  623 
Hydrangea,  448,  556 

wild,  556 
Hydrangin,  556 
Hydrastine,  162,  770 
Hydrastis,  161,  448,  532 

alkaloids,  174,  175 

farming,  734.  735 
Hydrochinon,  176 
Hydrodictyon,  22 
Hydrophilous,  401 
Hydrophyllaceae,  670 
Hydropiper,  448 
Hymenenasa,  574 
Hymenium,  57 
Hymenocallis,  448,  492 


Hyoscyamus,  385,  448,  684 

branching  hairs  in,  289 

fruit,  409,  412 

structure  of  seed,  429 

tracheae  of,  274 
Hypecoum,  547 
Hypericaceae,  618,  620 
Hypericum,  448,  620 
Hypha,  41 
Hypnum,  85 
Hypocotyl,  299,  426 
Hypocrateriform,  388 
Hypodermis,  309 
Hypogeous  shoot,  321,  325 
Hyssop,  691 

garden,  679 

Hyssopus,     glandular     hairs 
in,  230 

hesperidin  in,  153 

Ice-plant,  529 
Icthyomethia,  448 
Idaeus,  448 
Idioblasts,  207,  208 
Ilex,  448,  600,  601 
Ilicaceae,  600 
Ilicin,  600 
Illicium,  448,  540 
Illipe,  659 
Imbricated,  389 
Impari-pinnate,  357 
Impatiens,  448,  604 
Imperfect  flower,  392 
Incumbent,  427 
Indefinite  inflorescence,  394 
Index,  refractive,  774 
India  Bdellium,  587 

rubber,  516,  592 

senna,  567 
Indian  cress,  579 

cucumber,  485 
root,  435 

fig,  626,  627 

hemp,  436 

licorice,  434 

mallow,  610 

pipe,  452,  644 

Suringi,  620 

tobacco,  710 

turnip,  477,  480 
Indican,  169,  574 
Indicus-a-um,  448 
Indigo,  527,  573 

blue,  180,  574 

forming  glucoside,  553 

wild,  573 
Indigofera,  573 

tinctoria,  180 
Indigotin,  180 
Inflatus-a-um,  448 
Inflorescence,  393,  394 
Influence  of  gravity,  301 
Infundibuliform,  388 
Infusorial  earth,  38 
Inhambane  copal,  574 


INDEX. 


791 


Injury  to  plants,  172 
Ink-ball,  335,  512 

gall,  335,  512 

tree,  597 
Innate,  381 

Inner  structure  of  leaf,  365 
of  root,  309 
of  stem,  338 
Inosit,  607,  636 
Insect  flowers,  718 
Insect  visitation  of  flowers, 

399 

Insectivorous      plants,     fer- 
ments in,  244 
Intine,  404 

Intrafascicular  cambium,  341 
Inula,  387,  448,  720 

hairs  in,  288 

phytomelane  in,  261 
Inulenin,  150,  726 
Inulin,  150,  725 
Inulinase,  242 
Invertase,  242 
Involucre,  395 
Involute,  364 
Iodine  in  seaweeds,  40 

solution,  761 

in  water,  760,  761 
lonon,  622 
Ipecac,  448,  699 

wild,  706 

Ipecacuanha,  440,  448 
Ipomcea,  448 
Iridaceae,  492 
Iridin,  169 
Iris,  332,  448,  492 
Iron  solutions,  761 
Irone,  234 

Ironwood,  454,  510,  659 
Irregular  flower,  393 
Irritability.  358 
Irvingia,  586 
Isatis,  553 

Islandicus-a-um,  448 
Isoetes,  97,  449 
Isometric  system,  764 
Isoptera,  621 
Isoquinoline,  166,  180 
Isosporous,  87 
Iva,  448 
Ivory,  vegetable,  endosperm 

in,  265 
Ivy,  441,  447 

English,  636 

ground,  68 1 

poison,  595,  596 
Ixina,  449 

Jaborandi,  449,  455,  582 
Jacaranda,  691 
Jack-in-the-pulpit,  477 
Jack-tree,  516 
Jalapa,  449 

substitute,  528 
Jamaica  dogwood,  575 


Jambosa,  631 
Jambuse  berries,  632 
Japanese  lacquer,  597 

medlar,  562 

aoy  bean,  576 
Japan-wax,  212 
Jateorhiza,  539 
Jatropha,  591 
Jellies,  fruit,  243 
Jelly,  Kaiser's  glycerin,  763 
Jequirity,  575 
Jessamine,  yellow,  661 
Jewel-weed  family,  604 
Jimson  weed,  443,  684 
Joannesia,  591 
Juglandales,  509 
Juglans,  449,  509,  5io 

cross-section  of  wood,  346 
Juglansin,  195 
Juglon,  179 

Julocroton,  hairs  in,  282 
Juncaceae,  493 
Juncus,  493 
Jungermania,  83,  85 
Juniper,  116 
Juniperus,  118 
Jussieua,  634 
Jute  fiber,  269 

Kadsura,  540 
Kaiser's  glycerin-jelly,  763 
Kalmia,  174,  449,  648 
Kamala,  449,  451,  592 

hairs  of,  285 
Kapac  oil,  6n 
Kavaine,  508 
Kava-kava,  177,  452,  508 
Ketones,  234 

Kidney  bean,  protein  in,  199 
Kiggelaria,  623 
Killing  agent,  755 
Kinic  acid,  655 
Kino,  449,  569 

American,  569,  571 

Brazil,  593 

eucalyptus,  631 
Kittool,  476 
Kittul,  476 
Kiurushi,  597 
Kleister,  145 
Knot  weed,  456 
Kola  nut  tree,  614 
Krameria,  449.  57 1 
Kraunhia,  575 
Kristallsand,  188 
Kuhnia  (Wisteria),  449 
Kuhnistera,  449 
Kumquat  orange,  584 

Labellum,  388 
Labiatae,  449,  673 
Laburnum,  575 
Lac,  597 

Japanese,  597 

tree,  245 


Laccase,  597 
Laccases,  245 
Lace-tree,  628 
Lacinaria,  449,  722 
Laciniatus-a-um,  449 
Lacquer,  black,  245 

Japanese,  597 

trees,  597 
Lactarius,  65 
Lactuca,  449,  712 

milk-juice  of,  241 
Lactucarium,  241,  44*    712 
Lady's  mantle,  435 

slipper,  443 

thumb,  455 
Laetia,  623 
Laevulose,  155 
Lafaensia,  628 
Lagerstrcemia,  629 
Lagetta,  628 
Lamellae,  259 

middle,  254 

secondary,  255 
Lamina,  348,  385 
Laminaria,  30 
Lamium,  449 
Lanate,  354 
Lanceolatus-a-um,  449 
Landolphia,  241 
Langsdorffia,  519 
Langsdorffii,  449,  571 
Laplaceae,  618 
Laportea,  449,  517 
Lappa,  449 
Larch,  tannin  in,  206 
Larix,  118 

Larkspur,  443,  535,  574 
Lateral  branches,  312 

root,  301,  312 
Laterifolius-a-um,  449 
Laticiferous  vessels,  240 
Latex,  238,  546 
Lathyrus,  450,  576 
Lauraceae,  450,  544 
Laurel,  450,  544 

bay,  461 

great,  647 

ground,  444 

mountain,  648 

noble,  544 

nut,  212 
oil,  619 

sheep,  449,  648 

spurge,  627 
Laurus,  544 
Lavandula,  450 

hairs  in,  282,  284 
Lavender,  450,  676 

pollen   of,  404 

sea,  450 

spike,  676 

true,  676 

Lawsonia,  450,  629 
Layer,  resinogenous,  226 
Leaf,  apex  of,  354 


792 


INDEX. 


Leaf,  base  of,  356 

bifacial,  366 

climber,  324 

dorsiventral,  366 

functions  of,  350 

inner  structure  of,  365 

margin  of,  356 

mold,  formation  of,  249 

netted-veined,  353 

outer  morphology  of  leaf, 
348 

palmi-nerved,  353 

parallel- veined,  352 

reticulate,  353 

simple,  348 

teeth,  glandular,  283 

unifacial,  366 

venation,  352 
Leaflets,  356 
Leather,  dye,  633 

wood,  444,  627 
Leaves,  299,  348 

anatomical  differences  in, 
370 

autumn,  178 

bifacial,  349 

compound,  356 

cylindric,  349 

decay  of,  250 

divergence  of,  363 

dorsiventral,  349 

equitant,  349 

foliage,  1 20 

forms  of,  354 

modified,  364 

movement  of,  357 

scale,  1 20 

sporangial,  120 

surface  of,  353 

sword-shaped,  349 

texture  of,  354 
Lecanora,  74 
Lecidea,  75 
Lecithin,  214 
Lecythidaceae,  629 
Lecythis,  629 
Ledum,  450 
Leek,  485 
Legume,  419 
Legumelin,  195 
Legumin,  195,  576 
Leguminosae,  450,  567,  575 
Lemna,  300 
Lemnaceae,  450,  478 
Lemon,  450,  584 

oil,  584 

protein  in,  199 
Lens,  450,  576 
Lenticels,  291,  292 
Lenticus,  450 
Lentil,  450,  576 

protein  in,  199 

starch  in,  148 

sugar  in,  157 
Lentus-a-um,  450 


Lenzites,  62 
Leontin,  538 
Leonurus,  450,  682 
Lepargyreea,  628 
Lepidium,  450,  544 
Lepidodendron,  100 
Leptandra,  450 
Leptilon,  713 
Leptome,  276,  312 
Leptospermum,  632 
Lettuce,  449 

poison,  712 

Leucadendron,  450,  517 
Leucaena,  575 
Leuco-compounds,  179 
Leucoplastids,  136,  137 
Leucosin,  195 
Leucospermum,  518 
Leucothce,  648 
Levisticum,  450,  643 
Levo-glucose,  155 
Levulose,  155,  563 
Lianas,  324 
Liane,  324,  602 
Libriform,  270 
Lichens,  71 

color  in,  179 

economic  uses  of,  73 

on  Rhamnus   Purshianus, 
292 

roots  of,  73 
Licorice,  568 

fern,  96 

section  of,  271 

Spanish,  568 

wild,  704 

Life-processes,  134 
Light  relation  of  leaves,  349 

shoot,  329 
Lignin,  256,  580 
Lignocellulose,  256 
Lignone,  256 
Ligulate  flower,  711 
Ligule,  356 
Liguliflorae,  711 
Ligusticunij  450 
Ligustrum,  450,  66 1 
Lilac,  460 

garden,  66 1 
Liliaceae,  450,  485 
Liliales,  485 
Liliiflorae,  485 
Lilium,  485 
Lily,  450,  485 

lotus,  453 

of  the  valley,  442,  485,  487 

spider,  448 

yellow  pond,  453 
Lima  beans,  protein  in,  199 
Limb,  386 
Lime  fruit,  584 

tree,  608 
Limnophila,  358 
Limonene,  583 
Limonium,  450 


Limonu-m,  450,  584 
Linaceae,  450,  579 
Linalool,  233,  564,  583 
Linalyl  acetate,  234 
Linamarin,  169 
Linaria,  691 
Linariin,  691 
Linden,  461,  608,  609 

hesperidin  in,  153 
Lindera,  544 
Linen,  580 
Linodendron,  628 
Linseed,  oil  in,  213 
Linum,  579 

structure  of,  428 
Lion's  foot,  723 
Lippia,  450,  673 
Lippiol,  673 
Liquidambar,  450,  558 
Liquorice  (see  Licorice) 
Liriodendrin,  540 
Liriodendron,  450,  539 
Lithospermum,  450 
Litmus,  74 
Litsea,  546 

Liverworts,  76,  80,  82,  83 
Lobed,  356 
Lobelia,  384,  450,  710 

blue,  710 

red,  710 

section  of  leaf,  370 

seed-coat,  429 
Lobeliaceae,  450 
Loco,  574,  575 
Loculicidal,  412 
Locust,  457.  567,  576 
Loeffler's     methylene     blue, 

757 

Logania,  450,  66r 
Loganiaceae,  450,  661 
Logwood,  571 
Lomatia,  518 
Lonchocarpus,  575 
Lonicera,  450,  707 
Loosestrife,  451,  628 

purple,  628 
Lophophora,  625 
Lophophorine,  625 
Loranthaceae,  450,  518 
Loranthus,  518 
Lotus,  450,  532 
Lovage,  450,  643 
Lucerne,  577 
Luff  a,  710 
Luffa-sponge,  710 
Lumen,  false,  269 
Lunaria,  450,  553,  554 
Lungwort,  456 
Lupeol  acetate,  659 
Lupine,  451,  574 

seeds,  lecithin  in,  214 
Lupinidine,  575 
Lupinin,  575 
Lupinine,  575 
Lupinus,  451,  575 


INDEX. 


793 


Lupinus  luteus,    protein  in. 

Mammey  wine,  620*    ' 

199 

Mandarin,  584 

root  tubercles  on,  307 

Mandrake,  455 

Lupulin,  515 

Mangifera,  599 

Lupulus,  451 

Mango,  620 

Lusitanicus-a-um,  451 

Mangos,  599 

Luteus-a-um,  451 

Mangosteen,  446,  619 

Luzula,  493 

Mangostin,  619 

Lychnis,  451,  531 

Mangrove,  American,  630 

Lycoperdaceae,  59 

forest,  304 

Lycopodiaceae,  97,  45  1 

swamps,  631 

Lycopodium,  99,  213 

Mangrovin,  588 

Lycopus,  451 

Manihot,  594 

Lyngbya,  10 

Manna,  155,  451,  565,  661 

Lysigenous,  226 

Briancon,  118 

Lysimachia,  hairs  in,  282 

of  Israelites,  74 

Lythraceae,  628 

Persian,  155 

Lythrum,  400,  451,  628 

Mannit,  563 

Mannitol,  155 

Mabea,  592 

Mannose,  169 

Macaranga,  593 

Manometer,  306 

Macassar,  519 

Maple,  434,  602 

Mace,  212,  451,  543 

sugar,  157 

protein  in,  200 

syrup,  602 

starch  in,  148 

Maracaibo  balsam,  572 

Macis  (see  Mace) 

Maranta,  496 

Maclura,  451,  516 

arrow  root,  496 

Maclurin,  180 

Marantaceae,  496    - 

Macrocystis,  30 

Marasmius,  58 

Maculatus-a-um,  451 

Marcescent,  388 

Madder,  697,  702,  703 

Marcgravia,  617 

Mad-dog  skullcap,  675 

Marcgraviaceae,  616 

Magnolia,  451,  539,  540 

Marchantia,  81 

Magnoliaceae,  539 

Marginal,  451 

Magnolin,  540 

Marginalis-e,  451 

Magonia,  604 

Marginicidal,  411 

Mahogany  family,  588 

Margin  of  leaf,  356 

tree,  589 

Mariana,  451 

Mahonia,  trailing,  537 

Marigold,  387,  7i8 

Mahurea,  619 

bur,  438 

Maidenhair,  434,  439 

marsh,  439 

Maize,  462 

Marilandicus-a-um,  452 

Majalis,  451 

Maritimus-a-um,  451 

Majorana,  451 

Marjoram,  451 

Major-us,  451 

sweet,  679 

Malabanthri  folia,  568 

wild,  454,  679 

Malambo  bark,  592 

Marking  tree,  East  Indian, 

Male  generative-cell,  298 

597 

Mallotus,  451,  591 

Marmelos,  451 

hairs  of,  285 

Marrubium,  451,  676 

Mallow,  609,  611 

Marsdenia,  66P 

glade,  453 

Marsh  elder,  448 

Indian,  610 

Marshmallow,  435,  609 

rose,  448 

Marsilea,  451 

Malpighia  glabra,  tannin  in, 

Marsilia,  94,  95 

206 

Marsupium,  451 

Malpighiaceae,  589 

Marvel-of-Peru,  528 

Maltase,  242 

Massoy  bark  oil,  546 

Maltose,  155 

Mastic,  452,  599 

Malva,  611 

tree,  450 

Malvaceae,  451,  609 

Mastigocoleus,  8 

Malvales,  607 

Mat6,  600 

Mamillosus-a-um,  451 

germination  of,  730 

Mammea,  620 

Matico,  452,  504 

Mammei  apple,  620 

section  of  leaf,  371 

Matisia,  612 
Matricaria,  452,  715 
Mawseed,  547 
May  apple,  538 
Mayflower,  649 
Maysin,  195 
Maytenus,  602 
May  weed,  442 
Meadow  beauty,  634 

sweet,  459 
Meal,  mountain,  39 
Measurement,  microscopic, 

7S4 

Medeola,  485 
Medicago,  577 

ferment  in,  244 
Medicinal  plants,  cultivation 

of,  727 

Medicus-a-um,  452 
Medinilla,  634 
Medlar,  Japanese,  562 
Medullary  rays,  314 
Megasporangium,  108,    298, 

375 
Megaspore,  86,  298 

germination  of,  298 
Megasporophylls,  108,  375 
Melaleuca,  452,  632 
Melastoma,  634 
Melastomataceae,  633 
Melia,  588 
Meliaceae,  588 
Melibiose,  155 
Melilotus,  452 
Melissa,  452,  679 
Melon,  441,  454 

cucumber,  443 

musk,  protein  in,  199 

tree,  624 

Membrane,  primary,  255 
Memecylon,  634 
Mendel's  Law,  132 
Menispermum,  539 
Menispermaceae,  538 
Menispermum,  fibrovascular 
bundle  of,  337 

woody  vine  of,  322 
Menispine,  539 
Mentha,  452,  678,  384 

species  of,  676 
Menthol,  233 

Menyanthes,  452,  664,  665 
Menyanthin,  664 
Mercurialis,  452,  593 
Mercuric  chloride,  as  fixing 

agent,  756 
Mericarp,  417 
Meristems,  253,  254,  291 
Mermaid's  hair,  10 
Mescal,  492 

buttons,  625 
Mescaline,  625 
Mesembryanthemum,  529 
Mesocarp,  410 
Mesophyll,  366 


794 


INDEX. 


Mestome,  272 

sheaths,  367 

strand,  313,  341,  342,  343 
Mesua,  619 
Metabolism,  252 
Metachlamydeae,  504,  643 
Methyl  salicylate,  234 
Methylene  blue,  as  staining 

agent,  757 

Methysticin,  177,  508 
Methysticum,  452,  508 
Metroxylon,  475 
Meum,  452 

Mexican  linaloe  oil,  588 
Mezereum,  443,  452,  627 
Michelia,  540 
Microcarpus-a-um,  452 
Micrococci,  14 
Micrometer,  754 
Micrometry,  754 
Micron,  754 
Micro-polariscope,  764 
Micropyle,  425 
Microscope,  ultra,  765 
Microscopic      measurement, 

754 

Microsomata,  136 
Microsomes,  136 
Microspermae,  496 
Microsporangia,  120,  298 
Microspore,  298,  375 

germination  of,  298 
Microsporophylls,  105,  375 
Microtome,  749 
Midrib,  353 

Mignonette,  120,  457,  554 
Mikania,  452 
Milaceus-a-um,  452 
Mildews,  44 
Milfoil,  434 
Milk,  clotting  of,  244 

juice,  238 

ropy,  244 

vetch,  437 
Milkweed,  437 

family,  668 
Milkwort,  455 

family,  589 

white,  589 
Millefolium,  452 
Millet,  starch  in,  148 
Millettia,  575 
Millimeter,  754 
Mimosoideae,  567 
Mimusops,  659 
Mineral  cellulose  walls,  258 
Mint,  449,  452 

cat,  453,  680 

family,  673 

horse,  452 
Mio  Mio,  723 
Miocene,  117 
Mirabilis,  528 
Mistletoe,  450 

American,  531 


Mistletoe,  European,  518 

family,  518 

oak,  518 

Mitchella,  452,  697,  704 
Mitella,  452,  556 
Mitrewort,  452,  556 

false,  556 

Moccasin  flower,  498 
Mock  orange,  556 
Modified  leaves,  364 

roots,  306 
Mold,  black,  45 

water,  42 
Mollis-e,  452 
Monandrous,  381 
Monarda,  452,  679 

oil,  680 

Monkey-bread  tree,  612 
Monkey-pot  tree,  629 
Monkshood,  434 
Monniera,  452 
Monocarpia,  542 
Monoclinic  crystals,  183,  184 
Monocotyledons,  120,  463 
Monoecious,  392 
Monosaccharose,  154 
Monotropa,  452,  644 
Montanus-a-um,  452 
Moonseed,  Canada,  322,  539 

family,  538 
Moonwort,  438,  450 
Moraceae,  513 
Morchella,  58 
Morel,  58 
Morinda,  704 
Morindin,  170,  704 
Moringa,  223,  554 

pterygosperma,  212 
Moringaceae,  554 
Morning  glory,  448,  668 
Morphine,  547 
Morphology,  i 
Morus,  452,  517 
Moss,  bird's  nest,  103 

club,  97,  451 

groups,  84 

Iceland,  73,  440 

Irish,  31 

reindeer,  74 

scale,  83 

sea,  441,  446 
Mother-clove,  631 
Motherwort,  450,  682 
Mould  (see  Mold) 
Mountain  ash,  459 

elder,  706 

laurel,  648 

Mounting  of  specimens,  762 
Mounts,  permanent,  763 
Mourera,  556 
Movements  of  leaves,  357 
Moxa,  725 
Mucedo,  45 
Mucilage,  218,  565 

chemical  classification, 222 


Mucilage,  forms  of,  221 

in  sassafras,  263 

walls,  257 
Mucor,  45 
Mucuna,  452,  576 
Mugwort,  common,  719 
Mulberry,  452 

black,  517 

family,  513 

fruit,  409 

white,  517 
Mullein,  691 

hairs  of,  286 
Mundulea,  575 
Muntingia,  609 
Muricatus-a-um,  453 
Musa,  496 
Musaceae,  496 
Musci,  84 
Mushrooms,  434 

common,  59 

edible,  58 

lecithin  in,  214 

poisonous,  58 

propagation,  56 
Muskmallow,  434 
Musk-melon,  710 

protein  in,  199 
Musk  seed,  611 

substitute,  611 
Mustard,  438,  459 

ball,  453 

black,  552,  553 

family,  551 

fruit,  409 

garlic,  553 

hedge,  459,  553 

protein  in,  199,  200 

treacle,  445,  553 

white,  552,  553 

wild,  553 

yellow,     germination     of, 

299 

Mutation,  132,  247 
Mycelium,  41 
Mycose,  155 
Myelin,  forms,  215 
Myosotis,  453,  670 
Myrcene,  632 
Myrceugenia,  632 
Myrcia,  oil,  632 
Myrica,  211,  453,  508,  509 

cerifera,  212 

Nagi,  tannin  in,  206 

species,  508,  509 
Myricaceae,  508,  509 
Myricales,  508,  509 
Myricaria,  621 
Myricin,  594 
Myristica,  453,  543 
Myristicaceae,  543 
Myristin,  691 
Myrobalans,  633 

beleric,  633 

chebula,  633 


INDEX. 


795 


Myrobalans,  long,  633 

Node,  320 

(Edogonium,  25 

tannin  in,  206 

Nomenclature,  2 

CEnanthe,  643 

Myrosin,  243 

Botanical,  430 

(Enothera,  453,  634,  635 

Myroxylon,  623 

Nopalea,  627 

Officinalis-e,  453 

Myrrh,  442,  453,  586,  587 

North  American  papaw,  542 

Oil,  ajowan,  609 

Myrtaceae,  631 

Nostoc,  ii 

apeiba,  643 

Myrtales,  627 

Nucellus,  108,  124,  298 

apopin,  234 

Myrtiflorae,  627 

Nucleo-proteins,  194 

bay,  632 

Myrtle  family,  631 

Nucleoles,  136 

ben,  212 

tree,  453 

Nucleus,  2,  136 

benne,  691 

wax,  212,  453 

function  of,  140 

bergamot,  584 

Myrtus,  453,  632 

of  starch  grain,  144 

bigardia,  584 

Nuphar,  531 

cajeput,  632 

Nabalus,  723 

Nupharine,  531 

candle  nut,  213 

Naiadaceae,  466 

Nut,  420 

carapa,  589 

Naiadales,  466 

Nutation,  358 

cedar,    as   clearing   agent, 

Naked  flowers,  393 

Nutgall,  334,  446 

757 

Napaca,  453 

Nutlet,  420 

cedar-wood,  589 

Napaea,  612 

Nutmeg,   212,  453,  542,  543 

chaulmoogra,  214,  623 

Napellus,  453 

protein  in,  200 

cineol  containing,  544 

Naphthalene,       derivatives, 

starch  in,  148 

clove,  as    clearing    agent, 

179 

Nux-vomica,  453,  661 

757 

Naphthol  black  B.,  183 

endosperm  of,  265,  428 

coccos,  623 

Narcissus,  453,  492 

hairs  of,  286 

cocoa-nut,  212 

Nardus,  453 

Nyctaginaceae,  528 

Coniferae,  119 

Naringin,  169,  170,  585 

Nyctinastic,  361 

cotton  seed,  611 

Nasturtium  family,  579 

Nyctitropic,  361 

Crotdn,  Mexican,  591 

Natural  selection,  131 

Nymphaea,  453 

cumin,  643 

Navel  orange,  584 

Nymphaeaceae,  531 

curcas,  591 

Navicola,  37 

Nyssa,  453 

dill,  643 

Nectandra,  453,  546 

Nysso,  518 

essential,  as  clearing  agent, 

Nectar,  402 

757 

apparatus,  408 

Oak,  457,  5" 

Eucalyptus,  631 

poisonous,  402 

acorns,  148 

fatty,  546 

Nelumbo,  453,  532 

sugar  in,  157 

Fiji,  519 

Nepenthaceae,  555 

bark  of,  295 

fixed,  210 

Nepenthes,  555 

black,  512 

as  a  reserve,  217 

Nepeta,  453,  680,  681 

mistletoe,  518 

function  of,  235 

Nephelium,  603 

poison,  595 

globule,  detection  of,  752 

Nerium,  668 

western,  597 

kapac,  611 

Neroli,  583 

red,  512 

laurel-nut,  619 

Nerved  leaf,  352 

tannin  in,  206 

lemon,  584 

Nerves,  352 

tannin  in,  206 

marjoram,    as    clearing 

Nesaea,  628 

white,  511,  512 

agent,  757 

Neslia,  453,  554 

tannin  in,  206 

massoy  bark,  546 

Nessin,  628 

Oats,  437 

Mexican  linaloe,  588 

Netted-veined  leaf,  353 

protein  in,  199 

Monarda,  680 

Nettle,  461,  517 

starch  in,  148 

myrcia,  632 

dead,  449 

structure  of,  423 

Neroli,  583 

horse,  684 

sugar  in,  157 

non-drying,  691 

small,  517 

Obcordate,  355 

olive,  213,  660 

stinging,  287,  517 

Obtuse,  355 

orange  peel,  583 

wood,  449 

Obtusifolius-a-um,  453 

palm,  211,  474 

Nicotiana,  453,  688 

Occidentalis-e,  453 

palm-nut,  212 

Nicotianin,  688 

Ochrocarpus,  619,  620 

pepper,  Japanese,  585 

Nicotine,  688 

Ochroma,  612 

rose,  564 

Nigella,  453 

Ocimum,  679 

sandal,  518 

Niger-gra-grum,  453 

Ocotea,  546 

santal,  Australian,  519 

Nigger-toe,  630 

Ocotilla,  621 

sesame,  691 

Night-blooming  cereus,  625 

wax,  621 

spike,  679 

Nightshade,  459 

Ocrea,  520 

sweet  anise,  643 

deadly,  684 

Octomeles,  625 

tunga,  213 

enchanter's,  441,  634 

Ocular  micrometer,  754 

turpentine,      as      clearing 

Nitrogen  bacteria,  307 

Odontorhizon,  453 

agent,  757 

Nobilis-e,  453 

Odoratus-a-um,  453 

volatile,  225 

796 


INDEX. 


Oil,  volatile,  botanical  clas- 

Orange, protein  in,  199 

sification,  232 

root,  448 

characteristics  of,  231 

Seville,  583 

composition,  233 

sugar  in,  156 

culture  of  plants  yield 

sweet,  583 

ing,  747 

Orcein,  74 

formation,  235 

Orchid,  496 

micro-chemistry  of,  231 

Orchidaceae,  496 

water  fennel,  643 

Orchidales,  496 

Okra,  611 

Orchil,  75 

Olea,  660 

Orchis,  fringed,  447 

Oleaceae,  453,  660 

round-leaved,  499 

Oleander,  668 

white  fringed,  500 

cork  in,  293 

Orcin,  color  in,  179 

Oleandrin,  668 

Ordinary  ray,  774 

Oleo-resin,  225 

Orellin,  622 

Oleum,  453 

Organography,  I 

Cedralae,  589 

Organs,  nutritive,  3 

Lavandula,  676 

plant,  3 

Rosmarinus,  676 

sexual,  3 

Theobromatis,  612 

vegetative,  3 

Oleuropein,  661 

Orientalis-e,  454 

Olibanum,  587 

Origanum,  454,  679 

American,  587 

Cretian,  679 

Olive,  453,  660 

oil,  679 

family,  660 

Orlean,  621 

oil,  660 

Ornithogalum,  485 

tree,  660 

Ornus,  454 

Onagraceae,  634 

Orobanchaceae,  696 

Onion,  435.  485 

Orpine  family,  556 

sea,  461 

Orris  root,  332,  492 

sets,  327 

starch,  143 

starch  in,  148 

Orthotoschies,  363 

sugar  in,  157 

Oryza,  467 

Onoclea,  92,  453 

Oscillaria,  10 

Ononidis,  576 

Oscillatoria,  10 

Ononis,  576 

Osmosis,  251 

Ontogeny,  130 

Osmunda,  365,  454 

Oogonium,  5 

Ostrya,  454,  510 

Oomycetes,  42 

Otaheite  orange,  584 

Oosphere,  5 

Ovary,  120,  376 

Oospore,  5 

tissues  of,  406 

Opegrapha,  75 

Ovules,  376,  378 

Operculina,  453 

development  of,  124 

Operculum,  79 

forms  of,  379 

Opium,  241,  453 

positions  of,  379 

collection  of,  549 

Oxalidaceae,  579 

poppy,  546,  547 

Oxalis,  454,  579 

Optical  reactions,  773 

Oxidation,  252 

Opulus,  454 

Oxyacanthine,  539 

Opuntia,  454,  626,  627 

Oxycedrus,  454 

Opuntiales,  625 

Oxycoccin,  656 

Orange,  437,  441,  582 

Oxycoccos,  656 

bitter,  583 

Oxydases,  245 

blood,  584 

Oxygen,  252 

Curacao,  583 

in  fucus,  28 

G.  G.,  182 

Oxymethylanthraquinone, 

kidney-glove,  584 

176 

kumquat,  584 

Malta,  583 

Pachira,  611 

mock,  455,  556 

Paeonia,  454 

navel,  584 

Palaquim,  658 

osage,  451,  516 

Pale,  466 

otaheite,  584 

Palisade  tissue,  366 

Portugal,  583 

Palmae,  473 

Palmately-compound,  356 
Palmately-veined  leaves,  353 
Palmatus-a-um,  454 
Palmetto,  458 

saw,  459 

Palmi-nerved  leaf,  353 
Palm  oil,  474 
Palms,  473 
Palustris-e,  454 
Panax,  305,  454,  636,  638 
Pandanales,  463 
Pangium.igS,  623 
Panicles,  396 
Paniculatus-a-um,  454 
Panicum,  454 
Pansy,  622 
Papain,  244,  542,  624 
Papaver,  454,  546,  547 
Papaveraceas,  546 
Papaverales,  546 
Papaw  family,  624 

ferment  in,  244 

North  American,  437,  542 

tree,  624 
Papayotin,  624 
Paper,  Chinese  rice,  636 
Papilionaceous,  386 
Papilionatae,  567 
Papillae,  451 
Pappus,  711 
Paprika,  protein  in,  20O 
Papyrifer-a-um,  454 
Paracatechin,  607 
Para  cress,  724 
Paradise  grains,  494 
Parallel-veined  leaf,  352 
Para-nut,  629,  630 
Parasites,  40 
Pareira,  539 
Parenchyma,  forms  of,  262 

rays,  secondary,  314 

sheaths,  367 
Paricine,  546 
Parietales,  615 
Pari-pinnate,  357 
Parnasia,  209,  556 
Paronchia,  531 
Parrya,  553 
Parsley,  455 

garden,  643 

Parsnips,  protein  in,  199 
Partridge  berry,  697 
Parviflorus-a-um,  454 
Pasque  flower,  456 
Passiflora,  454,  623 
Passifloraceae,  623 
Passion  flower,  454,  615,  623, 
Patchouli  oil,  679 
Patchouly,  679 
Pauciflorus-a-um,  454 
Paullinia,  454,  603 
Paviin,  602 
Payena,  659 
Pea,  198,  576 

everlasting,  450 


INDEX. 


797 


Pea,  garden,  576 

germination  of,  299 

lecithin  in,  214 

protein  in,  199 

starch  in,  148 

sweet,  576 
Peach,  435,  562 

oil  in,  213 

protein  in,  199 

sugar  in,  156 
Peanut,  199,  576 

oil  in,  213 

plant,  401 
Pear,  457,  562 

prickly,  454,  526,  627 

protein  in,  199 
Peat,  bog,  250 

upland,  250 
Pectase,  243 
Pectin,  243,  563 

origin  of,  255 
Pectinase,  243 
Pectose,  243,  563 
Pedaliaceae,  691 
Pedatus-a-um,  454 
Pedicel,  393 
Peganum,  581 
Pelargonium,  579 
Pellitory,  435,  457,  714 
Pellotine,  625 
Pelosine,  546 
Peltatus-a-um,  454 
Pencils,  117 
Penicillium,  49 
Pennatifolius-a-um,  454 
Penny  cress,  field,  553 
Pennyroyal,  447 

American,  676 
Pentalostigma,  593 
Pentapetes,  615 
Pentastichous,  363 
Penthorum,  454,  556 
Pentose,  154 
Peony,  454 
Pepo,  420,  454,  708 
Pepper,  455 

African,  687 

black,  504,  505 

cayenne,  200,  687 

grass,  553 

long,  504 

moor,  585 

picking,  567 

protein  in,  200 

red,  439,  688 

starch  in,  148 

water,  448 

white,  504 
Pepperidge,  453 
Peppermint,  676,  678 

camphor,  233 

culture,  746 
Peramium,  503 
Pereirae,  454 
Perennial  herb,  330 


Perezia,  723 
Perfect  flower,  392 
Perfoliate,  356,  454 
Perfoliatus-a-um,  454 
Perforatus-a-um,  455 
Perianth,  382 
Periblem,  253 
Pericambium,  312 
Pericarp,  410 
Pericycle,  312 
Periderm,  291 
Perigynous,  389 
Perisperm,  425 

structure  of,  429 
Peristome,  79 
Periwinkle,  668 
Permanent  mounts,  making 

of,  763 

Peronospora,  43 
Persea,  455 
Persian  tobacco,  688 
Persicaria,  455 
Persimmon,  444,  660 

fruit,  659 

Japanese,  660 
Persistent,  388 
Personate,  388 
Persoonia,  518 
Pertusaria,  73 
Petals,  120,  374,  382 
Petiole,  348 
Petroselinum,  455,  643 
Peziza,  46 
Phaea,  575 
Phaeophyceae,  17,  28 
Phaius,  137 
Phallacese,  59 
Phanerogams,  5 
Phaselin,  195 
Phaseoleae,  hairs  in,  282 
Phaseolin,  195 
Phaseolus,  455,  576 

apical  region,  321 
Phasins,  198 
Pheasant's  eye,  434 
Phellandrene,  632,  643 
Phellogen,  290,  291,  313 
Phenol,  derivatives,  179 
Phenolases,  245 
Phenols,  234 

Phenyl  ethyl  alcohol,  564 
Philadelphia  fleabane,  713 
Philadelphus,  455,  556 
Phillipinensis-e,  455 
Phlobaphene,  203 
Phloem,  312 
Phloridzin,  169,  565 
Phloroglucin,  crystals,  762 

reaction,  256 

solution,  761 
Phlox,  455,  670 

tracheae  of,  274 
Phoenix,  475 

endosperm  in,  265 
Phoradendron,  518 


Phospholipines,  217 
Photosynthesis,     137,     299, 
350 

fixed  oils  in,  210 
Phycocyanin,  8 
Phycomycetes,  42 
Phyllanthus,  593,  594 
Phyllotaxis,  363 
Phylogeny,  129 
Physica,  73 

Physical  basis  of  life,  138 
Physiological  experiments, 

350 

Physiology,  i 
Physostigma,  455,  572 
Phytelephas,  473 

endosperm  in,  265 
Phyto-bezoars,  626 
Phyto-cecidien,  334 
Phyto-globulins,  193,  197 
Phytolacca,  455 

leaf,  section  of,  369 

root,  section  of,  318 
Phytolaccaceae,  528 
Phytomelane,  258 
Phytosterol,  214 
Phytovitellins,  193 
Pianeze  III  b,  70 
Picea,  109,  119,  455 
Pichi,  684 
Pickerel  weed,  482 
Picramnia,  hairs  in,  282 
Picrasma,  455,  585 
Picric  acid,  756 
Picric-sulphuric  acid,  as  fix- 
ing agent,  756 
Picro-crocin,  493 
Picrotoxin,  455,  539 
Piereskia,  627 
Pieris,  648 

hairs  in,  282 
Pigments,  138 

resins,  238 

respiration,  181 
Pignone,  117 
Pignut  hickory  trees,  333 
Pigweed,  441 
Pileus,  57 

Pilocarpus,  455,  582 
Pimelea,  627 
Pimenta,  455,  632 

starch  in,  148 
Pimpernel,  436,  455 
Pimpinella,  455,  639 
Pinaceae,  groups  of,  113 
Pinanga,  621 
Pine,  455 

Cuban,  113 

frankincense,  112 

great  sugar,  112 

loblolly,  112 

long-leaved,  113 

nut,  117 

oil  in,  213 

pitch,  112 


798 


INDEX. 


Pine,  prince's,  644 

seeds,  117 

spruce,  112 

sugar,  117 

swamp,  113 

torch,  112 

Weymouth,  106 

white,  106 

yellow,  113 
Pineapple,  436,  480 

ferment  in,  244 
Piney  resin,  621 
Pinguicula,  ferment  in,  244 
Pink,  443,  531 

Carolina,  66 1 

cultivated,  531 

lady's  slipper,  498 

root,  459 

Pinkster  flower,  646 
Pinnately-compound,  356 
Pinus,  455 

Strobus,  1 06 

sylvestris,  213 

tannin  in,  206 
Piper,   426,  455,    504,    506 
(see  also  Pepper) 

methysticum,  177 

species  of,  504 
Piperaceae,  504 
Piperales,  504 
Piperine,  161 

crystals,  771 
Piperitus-a-um,  455 
Pipitzahoic  acid,  723 
Pipsissewa,  455,  644 
Pircunia,  528 
Pirolaceae,  644 
Piscidia,  575 
Piscipula,  455 
Pistachio,  455,  599 
Pistacia,  208,  455,  597 
Pistil,  120,  376 

compound,  376 

different  types  of,  377 

simple,  376 
Pistillate,  392 
Pisum,  576 

ferment  in,  244 

germination  of,  299 
Pitch,  Burgundy,  119 

Canada,  119 
Pitcher-plant,  361,  458,  555 

family,  554 
Pith,  sassafras,  263 
Pithecolobium,  575 
Pityrodia,  hairs  in,  282 
Placenta,  377 

structure  of,  408 
Plaited,  389 
Planchonia,  629 
Plane  tree  family,  559 
Planifolius-a-um,  455 
Plant  hairs,  353 

henna, 450 
Plantaginaceae,  696 


Plantago,  455,  694,  696 

ferment  in,  244 
Plantain,  455,  694 

common,  694 

family,  696 

flowers,  400 
Plastids,  2,  138 
Platanaceae,  559 
Platanus,  559 
Plates,  sieve,  276 
Platinic  chloride,  165 
Platonia,  620 
Pleistocene  clays,  117 
Plerome,  253 
Pleurisy-root,  667,  668 
Pleurococcus,  20 
Pleurosigma,  36 
Plicate,  364,  389 
Plum,  456 

French,  562 

grape,  606 

oil  in,  213 

protein  in,  200 

sugar  in,  156 
Plumule,  127,  426 
Pod,  420 
Podophyllum,  455,  538 

rhizome  of,  324 
Podostemaceae,  556 
Podostemon,  455.  556,  679 
Point    of    origin    of   growth, 
144-  300 

of  vegetation,  300 
Poison,  arrow,  575,  593,  597, 
633,  662 

curare,  539 

fish,  539,  575,  604,  606 

ivy,  595,  596 

oak,  595 

snake,  antidotes,  539 
Poke  weed,  455 
Polariscope,  micro,  764 
Polemoniaceae,  670 
Polemoniales,  668 
Polemonium,  455,  670,  676 

family,  670 
Pollantin,  726 

Pollen,    120,    122,    298,    375, 
404,  726 

composition  of,  726 

method  of  gathering,  722 

pine,  107 

sac,  298 

toxic,  726 

tube,  in 

weight  of,  726 
Pollination,  in,  125,  397 
Pollinia,  123 
Polygala,  172,  455,  589 
Polygalaceae,  589 
Polygamous,  392 
Polygamus-a-um,  456 
Polygonaceae,  520,  574 
Polygonales,  520 
Polygonatum,  456,  483 


Polygonatum,    rhizome    of, 

.     325 

Polygonum,  456,  525,  527 
Polymnia,  720 
Polynesia,  631 
Polypeptides,  199 
Polypodium,  456 
Polypody,  456 
Polyporaceae,  59 
Polyporus,  456 

resins  in,  237 
Polytrichum,  77,  78,  85 
Pome,  420 

Pomegranate,  447,  457,  620- 
Pomelos,  584 
Pometia,  603 
Pond  lily,  yellow,  531 
Pond-weed  family,  466 
Pontederia,  482 
Pontederiaceae,  480 
Poplar,  456,  508 
Popowia,  542 
Poppy,  454,  548,  549 

California,  547 

celandine,  550 

family,  546 

horned,  446 

Mexican,  547 

oil,  547 
in,  213 

opium,  546,  547 

prickly,  436 

yellow,  550 
Populin,  169,  170,  508 
Populus,  456,  508 

species,  508 
Pores,  bordered,  275 

sieve,  276 

simple,  263 

water,  279 
Port  wine,  607 

coloring  of,  529 
Portulaca,  551 
Portulacaceae,  531 
Potassium  hydrate,  crystals, 
762 

iodide,  crystals,  762 
Potato,  688 

Chinese,  492 

family,  683 

phyto-globulins  in,  194 

plant,  688 

protein  in,  199 

starch,  142,  148 
in,  148 

manufacture  of,  148 
with  polariscope,  146 

substitute,  726 
Potentilla,  365,  456,  565 
Potometer,  351 
Pouzolzia,  517 
Pratensis-e,  456 
Precatorius-a-um,  456 
Prefloration,  389 
Prefoliation,  364 


INDEX. 


799 


Preservatives,  755 

Psidlum,  632 

Prickly  pear,  626 

Psoralea,  456,  574 

Pride  of  China,  588 

Psyllium,  456 

Primary  root,  301 

Ptelea,  456,  585 

cross-section  of,  310 

Pteridophytes,  86 

structure,  309 

Pteris,  456 

of  dicotyledonous  roots, 

Pterocarpus,  456,  569,  571 

345 

Pterospermum,  615 

of  stem,  338 

Puber-a-um,  456 

summary,  345 

Pubescens,  456 

summary,  317 

Pubescent,  353 

Primeverase,  658 

Puccinia  graminis,  69 

Primeverin,  658 

Puccoon,  450 

Primrose,  456 

Puffball,  58,  59 

evening,  453,  634,  635 

Pulegioides,  456 

family,  656 

Pulegone,  234 

Primula,  456,  656,  657 

Pulicaria,  456 

structure  of  flower,  407 

Pulmonaria,  456 

Primulaceae,  656 

Pulque,  492 

Primulales,  656 

Pulsatilla,  456,  537 

Primulaverin,  658 

Pulse,  450 

Prince's  feather,  527 

family,  567 

pine,  644 

Pulvinis,  360 

Principes,  473 

Pumpkin,  454 

Privet,  450,  66  1 

protein  in,  200 

Procumbens,  456 

sugar  in,  156 

Prolamins,  194,  195 

vine,  709 

Promycelium,  66 

Punica,  457,  629 

Propagation  by  cutting,  733 

Punicaceae,  629 

Propagative  organs,  298 

Purging  cassia,  567 

Prophylla,  393 

Purine,  167 

Protaceae,  517 

Purple  cone-flower,  724 

Protea,  species  of,  518 

gerardia,  693 

Proteacin,  517 

Purpureus-a-um,  457 

Proteales,  517 

Purshia,  565 

Protection  of  plants,  172 

Purshianus-a-um,  457 

Proteinase,  244 

Purslane,  531 

Proteins,  192 

Putamen,  410 

classification  of,  193 

Pycnidia,  73 

origin  of,  198 

Pycnoconidia,  73 

percentage  of,  199 

Pyrenoids,  17,  149 

toxic,  196 

Pyrethri  Flores,  718 

Protium,  586 

Pyrethron,  718 

Protococcus,  20 

Pyrethrum,  457 

Protonema,  78 

Pyridine,  166 

Protopine,  548,  55O 

Pyrocatechol,  204 

Protoplasm,  2,  134 

Pyrogallol,  204 

Protoplasmic  movement,  26 

Pyrola,  174 

Protoplast,  2,  134 

Pyrone,  180 

Prulaurasin,  169 

Pyrrolidine,  166 

Prune,  562 

Pyrus,  457,  562,  565 

protein  in,  200 

quercitin,  562 

sugar  in,  156 

Pyxidium,  413 

Prunifolius-a-um,  456 

Pyxis,  413,  630 

Prunum,  456 

Prunus,  560,  562,  565 

Quassia,  455.   457,   585,   586 

cork  of,  294 

Jamaica,  585 

ferments  in,  243 

Quebracho,  667 

section  of  wood,  346 

bianco,  457 

Pruriens,  456 

Colorado,  599 

Pseudo-^Egle  group,  583 

extract,  tannin  in,  206 

Pseudococcus,  627 

Queen's  root,  590 

Pseudoinulin,  150 

Quercitin,  169,  179,  180,  508, 

Pseudomonas,  307 

512,  562.  565 

Pseudotsuga,  114 

Quercitrin,  170 

Quercus,  457,  512 

bork  of,  295 

galls  on.  335 
Quillaja,  172,  457,  564 
Quillwort,  449 
Quina  blanca,  592 
Quince,  560,  562,  565 

Bengal,  451 
Quinine  herb,  664 
Quinoline,  166 
Quisqualis,  633 

Raceme,  394 
Racemosus-a-um,  457 
Radial  flower,  393 
Radial-longitudinal    section, 

749 

Radiate  head,  711 
Radicans,  457 
Radicle,  426 
Radish,  457 

color  in,  178 

protein  in,  199 
Ragweed,  435,  459,  726 
Rain  trees,  157 
Raisin,  606,  607 

sugar  in,  156 
Rajania,  492 
Ramie,  269,  517 
Ranales,  531 
Ranunculaceae,  532 
Ranunculus,  457,  537 

ferment  in,  244 
Rape-seed,  protein  in,  199 
Raphanus,  457,  553 
Raphia,  269 
Raphides,  186 
Raspberry  fruit,  415 

protein  in,  200 

red,  563 

sugar  in,  156 

syrup  of,  563 
Rattle-box,  442,  575 
Rattlesnake  plantain,  503 
Rattleweed,  574 
Ravensara,  546 
Ray-flowers,  395,  711 
Reactions,  optical,  773 
Reagents,  755 

alkaloidal,  163 

Mayer's,  164 

Sonnenschein's,  164 

special,  755 

Wagner's,  164 

Wormley's,  165 
Reaumuria,  621 
Rebandin,  713 
Receptacle,  375 

secretory,  226 
Reclinate,  364 
Red  gum,  574 

raspberry,  563 

root,  440 

wine,  607 
Reed.  439.  445 


8oo 


INDEX. 


Refractive  index,  774 
Regular  flower,  393 
Repand,  356 
Repens,  457 
Reptans,  457 
Reseda,  457,  554 
Resedaceae,  554 
Resene  resins,  237 
Reserve  layers,  425 
Resin,  236,  255 

balsamic,  225 

chaia,  621 

fossil,  237 

micro-chemistry  of,  231 

origin  of,  238 

piney,  621 

soft,  587 

Resinol  resins,  237 
Resinolic  acid  resins,  237 
Resins,  origin  of,  238 
Respiration,  350 
Reticulate,  354,  457 
Reticulatus-a-um,  457 
Retuse,  355 
Rhamnetin,  180 
Rhamnose,  154,  562 
Rhamnus,  457,  604 

bark  of,  342 

fruit,  422 

wood  of,  344 
Rhapontic,  457 
Rhaponticus-a-um,  457 
Rhatany,  449 
Rheedia,  619 
Rhein,  170 
Rheum,  457,  521 

species,  522 
Rhexia,  634 
Rhipsalis,  627 
Rhizogenous  layer,  312 
Rhizome,  325 
Rhizophora,  304,  630 
Rhizophoraceae,  630 
Rhodeose,  169 
Rhododendron,  457,  646 

glandular  hairs  in,  230 

hairs  in,  282 
Rhodophyceae,  17,  31 
Rhodymenia,  34 
Rhceadales,  546,  554 
Rhubarb,  457,  522 

garden,  522 

South  China,  522 
Rhus,  457,  595,  596,  597,  598 

ferment  in,  245 

hairs  of,  280,  284 

poisonous,  597 

species  of,  597 

tannin  in,  206 
Rhynchanthera,  634 
Ribes,  457,  558 

fruit,  418 
Riccia,  82 
Rice,  467 

protein  in,  199 


Rice,  starch  in,  148 
Ricin,  195,  196,  590,  611 
Ricinus,  196,  457,  591 

aleurone    grains    of,    194, 
428 

ferment  in,  244 

fruit,  410 

protein  in,  199 

seed,  426 
Ringent,  388 
Riuno-kiku,  726 
River-weed,  455 

family,  556 
Rivinia,  528 
Robin,  198 

Robinia,  457,  574,  576 
Robinin,  169 
Robustus-a-um,  457 
Roccella,  74 
Rocket,  447 
Rockrose,  447 
Rockweeds,  28 
Roman  chamomile,  713 
Root,  299 

abnormal  structure  of,  319 

absorption,  251 

adventitious,  301 

aerial,  306 

assimilation,  306 

belladonna,    cross- section 
of,  318 

branches,  319 

breathing,  306 

cap,  299,  301 

climber,  324 

contraction  of,  319        ; 

hairs,  299,  301,  309 

inner  structure  of,  309 

lateral,  301,  312 

modified,  306 

outer  morphology  of,  299 

phytolacca,     cross-section 
of,  318 

pressure,  252 

primary,  301 

structure     of     dicotyle- 
dons, 345 

primordia,  301 

secondary,  301 

stele,  313 

stock,  325 

tap,  301 

true,  299 

tubercle,  306 

tuberous,  305,  327 
Roripa,  553 
Rosa,  457,  564 
Rosaceae,  560 
Resales,  556 
Rose,  457,  564 

apple,  632 

bay,  457,  647 

camphor,  564 

family,  560 

geranium,  579 


Rose,  hip,  409 

oil,  564 

petals,  564 

tea,  629 

wood,  544 
Rosemary,  457 
Roseus-a-um,  457 
Rosin,  weed,  459,  723 
Rosmarinus,  457,  676 
Rostratus-a-um,  458 
Rotate,  388 
Rottlerin,  180,  592 
Rotundifolius-a-um,  458 
Rubber,  India,  241,  592 

trees, ,241 
Ruberithrinic,  169 
Ruber-ra-rum,  458 
Rubia,  702 
Rubiaceae,  697 
Rubiales,  697 
Rubus,  458,  563 

cork  in,  293 

fruit,  416 
Rudbeckia,  723 
Rue,  458 

anemone,  535 

family,  581 

garden,  585 

meadow,  460 
Ruellia,  694 
Rugose,  354 
Rugosus-a-um,  458 
Rum,  bay,  632 
Rumex,  458,  523 
Runner,  325 
Rush,  458 

bog,  449 

family,  493 

matting,  493 

scouring,  96 

soft,  493 

spike.  444 

wood,  493 
Rust,  wheat,  69 
Ruta,  458 
Rutaceas,  581 
Rutin,  170,  585 
Rye,  458,  467 

lecithin  in,  214 

protein  in,  199 

starch  in,  148 

sugar  in,  157 

Sabadilla,  458 
Sabal,  458,  473 
Sabbatia,-664 
Sabina,  115,  458 
Sable  tetraedrique,  188 
Sabodilla  tree,  659 
Sac,  pollen,  120 
Saccate,  388 
Saccharomyces,  47 
Saccharomycetes,  47 
Saccharose,  154,  155 
Saccharum,  458,  467 


INDEX. 


801 


Sacci,  492 
Safflower,  387,  719 

oil  in,  213 

yellow,  720 
Saffron,  442,  493 

meadow,  442 
Safranin,  as  staining  agent, 

757 
Sage,  458 

garden,  676 

hairs  of,  284 
Sageretia,  606 
Sagittaria,  465 
Sago,  475 

palms,  475 

starch,  475 
Sagrada,  440 
Saigonicus-a-um,  458 
Salegenin,  700 
Salicaceae,  508 
Salicales,  508 
Salicin,  169,  170,  508 
Salicylic  aldehyde,  564 
Salix,  458,  508 

tannin  in,  206 
Salsify,  461 

Salt,  table,  source  of,  556 
Salvia,  458,  676 

hairs  of,  230,  285 
Samadera,  586 
Samara,  420,  510,  602 
Sambucus,  458,  706 

cork  in,  293 
Sambunigrin,  169 
Sanctus-a-um,  458 
Sandal,  oil,  518 

tree,  458 

wood,  458 

family.  518 
Sandarac,  119 
Sand-box  tree,  592 
Sanguinaria,  458,  548,  550 

latex,  241 
Sanicula,  458 
Santal,  bastard,  581 

oil,  Chinese,  519 
Santalaceae,  518 
Santales,  518 
Santalinus-a-um,  458 
Santalol,  519 
Santalum,  458,  518 
Santonin,  719 
Sap,  ascent  of,  252 

cell,  134 

Sapindacea?,  602 
Sapindales,  594 
Sapindus,  603 
Sapium,  594 
Sapodilla  family,  658 
Saponaria,     172,    458,     53O, 

531 

Saponarin,  169 
Saponin,  171,  575,  603, 611 

occurrence  of,  172 
Sapotaceae,  658 


Sapotilla,  659 
Sapotoxin,  170 
Sappan,  439 
Saprolegnia,  42 
Saprophytes,  40 
Sapucaya  nut,  629 
Sarcocarp,  40,  410 
Sarcophyte,  519 
Sargassum,  31 
Sarracenia,36i,  458,  554,555 
Sarraceniaceas,  554 
Sarraceniales,  554 
Sarracenine,  554 
Sarsaparilla,  487 

wild,  637 
Sassafras,  458,  544 

mucilage  in,  263 

oil,  544 

Sativus-a-um,  458 
Satureia,  679 
Savin,  119 

Savory,  summer,  679 
Saxifragaceae,  556 
Saxifrage  family,  556 

golden,  441,  556,  557 
Scabiosa,  708 
Scadens,  458 
Scale,  seminiferous,  108 
Scammonia,  458 
Scammony,  458 

root,  669 

Scarlet  sumac,  597 
Scatol,  519 
Schinopsis,  599 

tannin  in,  206 
Schizandra,  540 
Schizogenous,  226 
Schizo-lysigenous,  226 
Schizomycetes,  12 
Schizophyceae,  8 
Schizophytes.  7 
Schulze's    cellulose    reagent, 
760 

macerating  solution,  761 
Scilla.  458 
Scillain,  170 
Scirpus,  458,  472 
Scitamineae,  493 
Scitaminales,  493 
Scleranthus,  531 
Sclerenchyma,  266 
Sclerenchymatous  fibers,  268 
Sclerocarya,  599 
Sclerotium,  52 
Scolopendrium,  458 
Scoparia,  458 
Scopolia.  684 

fruit,  412 

tracheae  in,  274 
Scopolin,  170 
Scotch  broom,  569 
Scrophularia,  691 
Scrophulariaceae,  688 
Scullion,  485 
Scurvy  grass.  553 


Scutellaria,  384,  458,  673 
Scytonema,  72 
Sea  bean,  575 

Island  cotton,  610    ' 

lettuce,  25 

weed,  435 

protein  in,  200 
Secale,  458,  467 
Secondary  corter.,  312,  313 

roots,  301 

structure,  313 

of  stems,  summary,  345 
summary,  317 
Secretory  canals,  228 

cavities,  227 

cavity    in    pines,  107 

cells,  226 
Sections,  749 

making  of,  749 
Sedge,  439,  472 
Sedum,  458,  556 

purpurascens,  368 
Seed,  379 

development  of,  125 

dispersal,  427 

inner  structure  of,  427 

outer  morphology  of,  423 

pans,  729 

plants  grown  from,  728 

structure  of,  424 
Selaginella,  86,  98-10^ 
Semecarpus,  458 
Sempervirens,  459 
Sempervivum,  556 
Seneca  root,  459 
Senecio,  459 
Senega,  459,  589 

Texas,  589 

white,  589 
Senegal,  459 
Senna,  440,  459,  567 

Alexandria,  567 

American,  360 

hairs  of,  285 

India,  567 

Tinnevelly,  367 

Tripoli,  567 
Sepals,  120,  374,  382 
Septa,  411 
Septicidal,  411 
Septifragal,  411 
Sequoia,  117  . 
Serenra,  459,  473 
Sericeous,  354 
Serotin,  169 
Serotinus-a-um,  459 
Serpentaria,  459,  520 

Southern,  521 
Serrate,  356 
Serrulatus-a-um,  459 
Sesame,  459 

oil  in,  213,  691 
Sesamum,  459,  691 
Seudo  tanga,  119 
Seven  barks,  556 


802 


INDEX. 


Sexual  generation,  298 

spore,  298 
Shaddock,  584 
Shea  butter,  212,  659 
Sheep  laurel,  648 

sorrel,  524 

Shepherd's  purse,  439,  554 
Shield  fern,  437 
Shikimi,  540 
Shoot,  299 

aerial,  329 

axis,  299 

creeping,  304 

epigeous,  321,  322 

hypogeous,  321,  325 

overground,  321 

subterranean,  329 

underground,  321 

undeveloped,  321 
Shorea,  621 
Shoyu,  577 
Shrubs,  329 
Sida,  611 
Siejas,  519 

Sierra  Leone  copal,  574 
Sieve,  276 
Sigillaria,  100 
Silene,  hairs  in,  282 
Silica,  202 

forms  of,  1 88 
Silique,  420,  459 
Silk,  269 

dye,  625 
Silk  weed,  437 
Silkworm,  food,  517 
Silphium,  723 
Silver-leaf  poplar,  508 
Simaba,  459 
Simaruba,  586 
Simarubacese,  585 
Simple  leaf,  348 
Sinalbin,  169,  170 
Sinapis,  459,  553 

germination  of,  299 
Sindor  balsam,  621 
Sinensis-e,  459 
Sinigrin,  169,  170 
Sinuate,  356 
Sisal  fiber,  269 
Sisymbrium,  459,  553 
Skullcap,  458,  673 
Skunk  cabbage,  478,  480 
Sleep  movements,  361 
Slime  molds,  2 
Sloanea,  609 
Small  nettle,  517 

Solomon's  seal,  483 
Smartweed,  448 
Smilacina,  484 
Smilax,  459,  485 

species  of,  487 
Smut,  461 

corn,  67 
Snakehead,  441 
Snakeroot,  459 


Snakeroot,  black,  458,  532 

Canada,  520 

Virginia,  520 
Sneeze-weed,  447,  723 
Snow-ball,  705 
Snow  berry,  460,  707 
Soap  bark,  564,  565 

berry  family,  602 

plants,  171 
Soapwort,  458,  520 
Socotrinus-a-um,  459 
Soda,  plants  yielding,  530 
Sodium  in  seaweeds,  28 
Soft  galls,  334 
Soil  acidity,  249 

bacterium,  307 

organic     constituents     of, 

250 

Soja  beans,  199 
Solanaceae,  683 

flowers  of,  385 
Solanidine,  688 
Solanine,  172,  684 
Solanum,  385,  459,  684 

fruit,  412 

Solidago,  459,  521,  722,  726 
Solomon's  seal,  456 
Solution,     Beale's     carmine, 
760 

Bohmer's       haematoxylin, 
760 

chloral-iodine,  761 

chlor-zinc-iodine,  760 

copper  acetate,  761 

Delafield's     haematoxylin, 
760 

Grenadier's        borax-car- 
mine, 760 

Grenacher's       haematoxy- 
lin, 760 

Hoyer's  picro-carmine,76o 

iodine  and  potassium  io- 
dide, 761 

iron,  761 

phloroglucin,  761 

Schulze's   macerating,  761 
Somnifer-a-um,  459 
Sorbile,  459 
Sorbilis-e,  459 
Sorbit,  563 
Sorbus,  459,  562 
Sorghum,  459,  467 

juice,  percentage  of  sugar 

in,  157 
Sorosis,  420 
Sorrel,  field,  524 

sheep,  524,  525 
Southernwood,  434 
Soy,  577 
Spadix,  394.  475 
Spanish  licorice,  568 

moss,  481 
Sparganiaceae,  463 
Sparganium,  464 
Spathe,  394,  478 


Spathiflorae,  475 

Spawn,  56 

Spearmint,  384,  676,  678 

plant  of,  326 
Special  reagents,  755,  761 
Specimens,  mounting  of,  762 
Spectroscope,  764,  765 
Speedwell,  462 
Sperm,  5 

Spermophytes,  100 
Sphaerites,  192,  678 
Sphasrobacteria,  13 
Sphagnum,  84,  85 
Sphere  crystals,  678 
Spicatus-a-um,  459 
Spice  bush,  439,  544 
Spider  wort,  461,  480 
Spigelia,  459,  661 

tracheae  of,  274 
Spignel,  452 
Spike,  394 

oil,  679 

Spikelet,  394,  469 
Spikenard,  453 
Spilanthes,  724 
Spilanthin,  724 
Spinach,  527 

protein  in,  199 

sugar  in,  157 
Spinacia,  527 
Spindle  tree,  445 
Spinose,  354 
Spiraea,  459,  564 
Spiral,  thickening,   develop- 
ment of,  272 
Spirogyra,  18 
Spleenwort,  437 
Sporangia,  375 
Sporangium,  4 
Spores,  3 

asexual,  4,  298 

sexual,  4,  298 

staining  of,  71 

swarm,  5 
Sporidia,  66 
Sporobolus,  467 
Sporogonium,  79 
Sporophylls,  375 
Sporophyte,  75 

embryo,  298 
Spring  beauty,  531 
Spruce,  109,  455 

beer,  119 

black,  112 

Douglas,  114 

Norway,  119 

pine,  112 

white,  tannin  in,  206 
Spurge,  445,  500,  590 
Squarrosus-a-um,  459 
Squash,  443 
Squaw-root,  695,  696 
Squaw  weed,  459 
Squill,  458,  461,  487 
Staff  tree,  440,  600 


INDEX. 


803 


Stage  micrometer,  754 
Staining  agents,  757 

of  bacteria,  16 

double,  762 
Stains,  755 
Stalk,  348 
Stamen,  120,  374,  375,  379 

different  types  of,  380 
Staminate,  392 
Staminodia,  391 
Staminodes,  391 
Staphisagria,  459,  535 
Star  apple,  659 

grass,  435 

of  Bethlehem,  485 
Starch,  140,  435 

assimilation,  140 

botanical   distribution   of, 
147 

Brazilian  arrow-root,  670 

characteristics  of,  145 

grain,  composition  of,  143 
development  of,  141 
structure  of,  143 

manufacture  of,  148 

occurrence  of,  143 

percentage  of,  148 

properties  of,  145 

reserve,  137,  143 

seen  with  the  micropolari- 
scope,  146 

sweet-potato,  670 

with  iodine,  147 
Stavesacre,  459,  535 
Stem,  299,  320 

branches,  320 

inner  structure  of,  338 

of  dicotyledons,  338 

outer  morphology  of,  320 

primary  structure  of,  338 

structure,  abnormal,  344 
dicotyledonous,  339 
primary,  summary,  345 
secondary,     summary, 
345 

underground,  325 
Sterculia,  615 

seeds,  615 
Sterculiaceae,  612 
Sterilization,  15 
Stick-lac,  238 
Sticta,  73 
Stigma.  120,  376,  378 

different  types  of,  377 

epithel.  406 

structure  of,  405 
Stillingia,  459,  590 
Stinck  weed,  460 
Stinging  nettle,  517 
Stink-wood,  546 
Stipa,  472 
Stipe  of  fungi,  57 
Stipules,  348 

function  of,  348 
Stitch-wort,  531 


St.  John's  bread,  440,  576 

wort,  448 

family,  620 
Stolon,  325 
Stoma,  279 
Stomata,  278,  367,  368 

on  leaves  of  Beta,  367 
Stonecrop,  458 

common  mossy,  556 

ditch,  556 

Virginia,  556 
Stoneworts,  26 
Storax,  460,  559,  660 
Stramonium,  460,  684 

fruit,  409,  412 

hairs  of,  284 

seed,  428 

tr.ansverse  section  of  mid- 
rib, 366 
Strawberry,  445,  566 

fruit,  409,  415 

garden,  566 

protein  in,  200 

wild,  567 

Striatus-a-um,  460 
Strigose,  354 
String  beans,  199 
Strobile,  375,  420 
Strobiles,  375 

Strophanthin,  169,  170,  171 
Strophanthus,  460,  666 

haiis  of,  284,  285 
Strophiole,  427 
Structure,  basis  of,  I 

of  wood,  347 

primary,  254,  309 
summary,  317 

secondary,  254 
summary,  319 

stem,     classification     of, 

341 

primary,  summary,  345 
Strychnine  crystals,  769 
Strychnos,  460,  661 
Stryphnodendron    polyphyl- 

lum,  tannin  in,  206 
Style,  120,  376,  378 

structure  of,  406 
Styloids.  183 
Stylophorine,  550 
Stylophorium,  550 
Styracaceae,  660 
Styraciflua,  460 
Styrax,  460,  558,  660 
Suberin,  257,  290 
Suberose,  257 
Sublimable  principles,  173 
Succisa,  708 
Succory,  441,  716 
Sucrose,  155,  527 
Sugar,  154 

beet,  52? 

protein  in,  199 

bush,  518 

cane,  467 


Sugar.cane.juice.percentage 
of  sugar  in,  157 

in  cereals,  percentage  of, 
156 

in  plants,  156 

in  vegetables,  156 
Sumach,  457,  595 

poison,  597 

scarlet,  597 

tanner's,  595 
Sumbul,  639 
Summer  savory,  679 
Sundew,  361  444,  554 
Sun-dial,  451 
Sun-flower,  712 

oil  in,  213 

seed-cake,  725 

seed,  protein  in,  199 
Sun's  energy,  138 
Suppressed,  391 
Surface  of  leaves,  353 
Suringi,  India,  620 
Survival  of  the  fittest,  131 
Suspensor,  125 
Suture,  dorsal,  377 

ventral,  377 
Swamp  pink,  485,  490 
Sweet,  444 

almond,  protein  in,  199 

anise  oil,  643 

balm,  679 

basil,  679 

cicely,  643 

fern,  509 

flag,  479 

gale,  509 

gum  tree,  450,  558 

marjoram,  679 

pea,  576 

potatoes,  protein  in,  199 
percentage  of  sugar  in, 

157 

starch,  670 
vine,  669 

scabious  fleabane,  713 

William,  531 

wine,  607 
Swertia,  460,  664 
Swietenia,  589 
Sycamore,  559 
Syconium,  420 
Sylvaticus-a-um,  460 
Sylvestris-e,  460 
Symmetrical,  flower,  392 
Sympetalae,  643 
Sympetalous,  385 
Symphonia,  620 
Symphoricarpos,  460,  707 
Symphytum,  460,  671 
Symplocarpus,  478,  480 
Synantherin,  150,  726 
Syncarpous,  376 
Synergids,  124 
Syngenesious,  382 
Synura,  n 


INDEX. 


Syringa,  455,  460,  661 
Syringin,  169,  661 
Syringopicrin,  661 

Tabacum,  460 

Table  salt,  source  of,  556 

Tacamahac,  439,  508,  613 

Bourbon,  618 

Brazilian,  618 

India,  618 

resins,  587 

West  Indian,  587 
Tagetes,  hairs  in,  288 
Talauma,  540 
Tallow  tree,  Chinese,  594 
Tamaricaceae,  621 
Tamarindus,  460,  569 
Tamarix,  621 
Tamonea,  634 
Tamus,  492,  709 
Tanacetum,  460,  720 
Tangential-longitudinal  sec- 
tion, 749 
Tangkawang,  621 
Tanner's  sumac,  595 
Tannides,  202 
Tannin,  202 

chemical  properties  of,  203 

distribution  of,  205 

idioblast,  207,  208 

in  galls,  335 

micro-chemistry  of,  204 

pathological,  207 

physiological,  207 
Tannol  resins,  236 
Tansy,  460,  720 
Tapetum,  121 
Tapioca  starch,  594 
Tap-root,  301 
Tapura,  606 

Taraktogenos  kurzii,  214 
Taraxacum,  239,  387,  460 
Taxus,  113 
Tea,  460,  617 

Appalachian,  600 

black,  618 

Brazilian,  600 

caffeine  in,  162 

cassine,  600 

chests,  625 

culture,  746 

family,  617 

green,  618 

Labrador,  450 

New  Jersey,  605 

Paraguay,  600 

germination  of,  730 

plant,  615 

rose,  629 

seed,  oil  in,  213 

substitute,  53 j,  634 

tree,  617 
Teaberry,  650 
Teak-tree,  .673 
Teak-wood,  673 


Teasel,  444,  707 
Technique,     bacteriological, 

14 

Tecoma,  691 
Tectona,  673 
Tegmen,  425 
Telegraph  plant,  361 
Teleutospores,  68 
Temperature,  247 
Tendril,  323 

climber,  324 
Tephrosia,  575 
Terebinthina,  460 
Terminalia,  633 
Terpenes,  233 
Terpinene,  679 
Terpineol,  632 
Terra  silicea  purificata,  38 
Testa,  425 

Testing  of  drugs,  248 
Tetradynamous,  381 
Tetragonal  crystals,  183 
Tetrameles,  625 
Tetrapanax,  636 
Teucrium,  460 
Texture  of  leaves,  354 
Thalictroides,  460 
Thalictrum,  460 
Thallophytes,  6 
Thallus,  6 
Thea,  460,  616 
Theaceae,  617 
Thein,  173,  176 
Thelephoraceae,  59 
Theobroma,  460,  612 
Theobromine,  612,  618 
Theophylline,  618 
Thistle,  712,  723 

blessed,  442 

milk,  451. 

star,  440 

Virgin  Mary's,  451 
Thlaspi,  553 
Thorn  apple,, 684 
Thorough  wort,  445,  712 
Thuja,  1 1 8,  460 
Thujone,  719 
Thyme,  460 

field,  441 

garden,  677 
Thymelaea,  628 
Thymelaeaceae,  627 
Thymol,  234,  678,  681 
Thymo-quinhydrone,  179 
Thymoquinone,  179,  681 
Thymus,  460 
Tiarella,  460,  556 
Tibouchina,  634 
Tick  Trefoil,  443 
Tilia,  461,  608,  609 

hesperidin  in,  153 

species  of,  609 
Tiliaceae,  609 
Tillandsia,  480 
Tinctorium,  460 


Tinctorius-a-um,  460 
Tissue,  121 

conjunctive,  313 

laticiferous,  296 

mechanical,  264 

milk,  296 
Tobacco,  453,  460,  688 

camphor,  688 

Indian,  710 

Persian,  688 

plant,  Virginia,  688 

Turkey,  688 

wild,  710 
Tococa,  634 
Toddy,  620 
Tolu,  balsam  of,  572 
Tolu-resinotannol,  572 
Toluifera,  461,  572 
Tomato  plant,  688 

sugar  in,  157 
Tomentose,  354 
Tomentosus-a-um,  461 
Toothed,  385 
Toringin,  562 
Tormentilla,  565 
Torus,  375,  389 
Touch-me-not,  448 
Touranose,  155 
Tous  les  mois,  496 
Toxalbumins,  196,  726 
Toxicodendrol,  595 
Toxicodendron,  461 
Toxylon,  516 
Tracheae,  273,  313 

markings  of,  273 
Tracheids,  275 
Trachylobium,  574 
Tradescantia,  461,  480 
Tragacanth,    218,   461,   569, 

570 
Tragopogon,  461 

hairs  in,  288 
Trailing  mahonia,  537 
Transpiration,  350 
Transverse  heliotropism,  349 

section,  749 
Trapa,  634 
Treacle  mustard,  553 
Tree  of  heaven,  434 
Trees,  329 

green  coating  on,  21 
Trefoil,  clover,  461 

bird's  foot,  450 
Trehalose,  155 
Tremellaceae,  59 
Triandrus-a-um,  461 
Triassic  period,  101 
Trichodesmium,  8 
Tricolor,  461 
Tricuspidatus-a-um,  461 
Trifolium,  461,  576 
Trilisa,  461 
Trillium,  461 
Trimorphic  flowers,  399 
Triosteine,  707 


INDEX. 


805 


Triosteum,  706 

Umbelliflorae,  636 

Triphyllus-a-um,  461 

Umbellularia,  461,  544 

Tristichous,  363 

Umbrella  tree,  540 

Triticum,  461,  467,  468 

Unguis,  385 

Trivial,  461 

Unifacial  leaf,  366 

Trivialis-e,  461 

Uniflorus-a-um,  461 

Tropagolaceae,  579 

Unisexual,  444 

Tropaeolum,  579 

flower,  392 

True  root,  299 

Unona,  542 

Solomon's  seal,  483 

Upas-tree,  516 

Truffles,  65 

Uragoga,  699,  7OO 

Trumpet-creeper,  691 

Urari  poison,  51? 

Truncate,  355 

Urceolate,  388 

Tsuga,  113,  118,  461 

Uredineae,  65 

Tuber,  326 

Uredospores,  69 

Tubercle,  root,  306 

Urena,  611 

Tuberin,  195 

Urginea,  461,  487 

Tuberose,  485 

Uroglena,  8,  10 

Tuberosus-a-um,  461 

Urtica,  461,  517 

Tubiflorae,  668 

Urticaceae,  51? 

Tubular  flowers,  711 

Urticales,  512 

Tuckahoe,  65 

Use  and  disuse,  131 

Tulip,  485 

Usitatissimus-a-um,  461 

bulb,  330 

Usnea,  73 

tree,  450,  539 

Ustilagineae,  65 

Tupelo,  453,  518 

Ustilago,  67.  461 

Turner  ic,  494 

Utricle,  420,  527 

Turmerol,  496 

Utricularia,  299 

Turnera,  623 

Uva-ursi,  461,  644 

Turneraceae,  623 

Uvularia,  485 

Turnip,  438,  553 

Indian,  436 

Vaccinium,  174,  653 

little,  453 

fruit,  417 

protein  in,  199 

Vacuole,  134 

sugar  in,  157 

Valerian,  462,  707' 

Turpentine,  118,  460 

garden,  707 

as  a  clearing  agent,  757 

Greek,  671 

Canada,  118 

wild,  707 

Strassburg,  119 

Valeriana,  462,  707 

Venice,  118 

Valerianaceae,  707 

Turpeth,  461 

Valerianales,  707 

root.  453 

Valerianella,  7.07 

Turpethum,  461 

Vallea,  608 

Turtlehead,  441,  691 

Valonia,  tannin  in,  206 

Tussilago,  387,  461,  723 

Valvate,  389 

Twin  leaf,  449 

Vanilla,  462,  497 

Twiner,  324 

grass,  472 

Types  of  mestome  strands, 

hairs  of,  284 

343 

leaf,  461 

Typhaceae,  463 

sugar  in,  157 

Vanillin,  173,  572 

Ulex.  575 

Variifolius-a-um,  462 

Ulfnaceae,  512 

Various  woods,  coarse  struc 

Ulmaria,  461 

tures  of,  346 

Ulmus,  461 

Varnish  tree,  597 

section  of  wood,  346 

Vasicine,  696 

species  of,  512 

Vateria,  621 

Ultra-microscope,  765 

Vatica,  621 

Ulva,  25 

Vaucheria,  22,  40 

Umbel,  394.  636 

Vegetable  agglutinins,  198 

Umbellales.  636 

bezoars,  577 

Umbellated,  461 

butter,  659 

Umbellatus-a-um,  461 

ivory,  473,  474 

Umbelliferae,  575,  636 

Vegetative  organ,  299 

fruit  of,  417 

Veins,  352 

Venation  in  Dicotyledons, 353 

Monocotyledons,  352 
leaf,  352 

Venenosus-a-um,  462 
Ventral  palisade  tissue,  366 

suture,  377 

Venus's  fly-trap,  362,  554 
Veratrum,  462,  485 

section  of  root,  320 
Verbain,  blue,  674 
Verbascum,  691 
hairs  of,  286 
hesperidin  in,  153 
Verbenaceas,  673 
Verbenas,  673,  674 
Vermilion,  597 
Vernation,  364 
Veronica,  462,  689 
Verrucose,  354 
Versatile,  380 
Versicolor,  462 
Verticillatus-a-um,  462 
Verus-a-um,  462 
Vervain,  673 

nettle-leaves,  673 
Vessels,  273,  313 
Vetchling,  450 
Viburnum,  462,  704,  705 
Vicia  faba,  199 
Vicianin,  169 
Vicilin,  195 
Victoralis,  462 
Victoria,  532 
Vignin,  195 
Villosus-a-um,  462 
Vinca,  668 
Vinifer-ra-rum,  462 
Viola,  462,  622 

glandular  hairs  in,  230 
leaf  of,  348 
quercitin,  622 
stem  in  section,  336 
stomata  in,  278 
structure  of  flower,  403 
Violaceae,  622 
Violet,  462 

dog's  tooth,  485 
English,  622 
family,  622 
leaf  of,  348 
sweet,  622 
Virginia  creeper,  607 

grape-fern,  365 
Virginianus-a-um,  462 
Virginicus-a-um,  462 
Viridiflorus-a-um,  462 
Viridis-e,  462 
Virosus-a-um,  462 
Viscine,  518 
Viscum,  518 
Vismia,  619.  620 
Vitaceae.  606 
Vitae,  arbor,  460 
Vitis,  462,  607 
Vittae.  637 


8o6 


INDEX. 


Volvox,  21 

White  clover,  colors,  178 

Vouacapoua,  436,  462 

wines,  607 

Vulgaris-e,  462 

Whortleberry,  654 

Wild  black  cherry,  560 

Wahoo,  600 

brier,  564 

Wake-robin,  437,  461 

caper,  591 

Walking  leaf,  439 

cherry,  561 

Wall,  composition  of,  254 

indigo,  573 

kinds  of,  258 

marjoram,  679 

marking  of,  260 

strawberry,  566 

mucilage,  257 

yam  root,  492 

origin  of,  254 

Willow,  458,  508 

pepper,  556 

herb,  440,  634 

thickening  of,  260 

flowers,  400 

Walnut,  449,  509 

Wind  flower,  436 

black,  509 

Wine,  607 

English,    cross-section    of 

light  colored,  607 

wood,  346 

mammey,  620 

family,  509 

port,  607 

oil  in,  213 

red,  607 

white,  509 

sweet,  607 

Waltheria,  615 

white,  607 

Wandering  Jew,  480 

Winterana,  622 

Washingtonia,  643 

Winteranaceae,  622 

Water,  247 

Winter  cress,  438 

arum,  439,  479 

Wintergreen,  644,  650 

cress,  553 

Winterin,  540     . 

fennel  oil,  643 

Winter's  bark,  540 

hemlock,  575,  642 

Wistarin,  575 

iodine,  761 

Wisteria,  462,  575 

leaf  family,  670 

Witch-hazel,  447,  558,  559 

lily  family,  531 

Witch's  brooms,  334 

melon,  710 

Wolfsbane,  434 

net,  22 

Wood,  317 

plantain,  466 

bass,  461 

pores,  279  ' 

carving,  117 

Wax,  210,  216,  277 

fibers,  270 

carnauba,  2,  4 

in  coal,  up 

crystalline,  216 

pulp,  117 

forms  of,  216 

red,  117 

Japan,  212, 

rush,  493 

myrtle,  211,  212,  509 

sorrel,  454,  544,  579 

ocotilla,  621 

structure  of,  346 

opium,  214 

Woodfordia,  628 

Wheat,  461,  467 

Woodruff  weed,  437 

grass,  434 

Wool,  269 

lecithin  in,  214 

Woolly,  354 

protein  in,  199 

Wormseed,  527 

starch  in,  148 

Spanish,  527 

sugar  in,  15? 

Wormwood,  434,  437,  719 

White  clover,  472 

hairs  of,  285 

Xanthium,  462,  723 
Xanthone,  180 
Xanthorhamnin,  169,  170 
Xanthosome,  480 
Xanthostrumarin,  723 
Xanthoxylum,  462,  582 
Xerase,  49 
Xylem,  312 
Xylopia,  541,  542 
Xylose,  169 
Xyrideales,  480 

Yam,  444,  492 

root,  wild,  322,  492 
Yarrow,  434,  452 
Yeast,  47 

dry,  lecithin  in,  214 

glycogen  in,  154 
Yellow  gum,  574 

pond  lily,  434,  531 
Yerba  Mate,  60 1 

Santa,  670 
Yew,  113 
Ylang-ylang,  542 
Yohimbi  bark,  702 
Yohimbihi  bark,  702 
Yohimbine,  702 
Yucca,  485 

Zanthoxylum,  581,  582 
Zanzibar  copal,  574 
Zea,  462,  467,  469 

root-tip,  300 
Zeora,  75 
Zeridine,  49 
Zeylonicus-a-um,  462 
Ziehl's  carbol-fuchsin,  757 
Zingiber,  462,  494,  495 
Zingiberaceae,  494 
Zizyphus,  606 
Zollikoferia,  hairs  in,  282 
Zoo-cecidien,  335 
Zoospores,  5 
Zostera,  466 
Zygadenus,  574 
Zygomorphic,  393 
Zygomycetes,  42 
Zygophyllaceae,  581 
Zygospore,  5 
Zymase,  244 


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